diff --git a/src/main/java/org/onosproject/yangutils/datamodel/HasType.java b/src/main/java/org/onosproject/yangutils/datamodel/HasType.java
new file mode 100644
index 0000000..e7a5c73
--- /dev/null
+++ b/src/main/java/org/onosproject/yangutils/datamodel/HasType.java
@@ -0,0 +1,32 @@
+/*
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.onosproject.yangutils.datamodel;
+
+import java.util.List;
+
+/**
+ * Represents the holder with type(s).
+ */
+public interface HasType {
+
+    /**
+     * Returns type list.
+     *
+     * @return type list
+     */
+    List<YangType<?>> getTypeList();
+}
diff --git a/src/main/java/org/onosproject/yangutils/datamodel/YangTypeDef.java b/src/main/java/org/onosproject/yangutils/datamodel/YangTypeDef.java
index 35998d4..49eafff 100644
--- a/src/main/java/org/onosproject/yangutils/datamodel/YangTypeDef.java
+++ b/src/main/java/org/onosproject/yangutils/datamodel/YangTypeDef.java
@@ -15,6 +15,8 @@
  */
 package org.onosproject.yangutils.datamodel;
 
+import java.util.LinkedList;
+import java.util.List;
 import org.onosproject.yangutils.datamodel.exceptions.DataModelException;
 import org.onosproject.yangutils.parser.Parsable;
 import org.onosproject.yangutils.utils.YangConstructType;
@@ -48,10 +50,11 @@
  *                | units        | 7.3.3   | 0..1        |-string           |
  *                +--------------+---------+-------------+------------------+
  */
+
 /**
  * Represents data model node to maintain information defined in YANG typedef.
  */
-public class YangTypeDef extends YangNode implements YangCommonInfo, Parsable {
+public class YangTypeDef extends YangNode implements YangCommonInfo, Parsable, HasType {
 
     /**
      * Default value in string, needs to be converted to the target object,
@@ -90,10 +93,17 @@
     private String units;
 
     /**
+     * List of YANG type, for typedef it will have single type.
+     * This is done to unify the code with union.
+     */
+    private List<YangType<?>> typeList;
+
+    /**
      * Creates a typedef node.
      */
     public YangTypeDef() {
         super(YangNodeType.TYPEDEF_NODE);
+        typeList = new LinkedList<>();
     }
 
     /**
@@ -180,7 +190,10 @@
      * @return the data type
      */
     public YangType<?> getTypeDefBaseType() {
-        return dataType;
+        if (!(getTypeList().isEmpty())) {
+            return getTypeList().get(0);
+        }
+        return null;
     }
 
     /**
@@ -189,7 +202,7 @@
      * @param dataType the data type
      */
     public void setDataType(YangType<?> dataType) {
-        this.dataType = dataType;
+        getTypeList().add(0, dataType);
     }
 
     /**
@@ -259,4 +272,9 @@
     public void setName(String name) {
         this.name = name;
     }
+
+    @Override
+    public List<YangType<?>> getTypeList() {
+        return typeList;
+    }
 }
diff --git a/src/main/java/org/onosproject/yangutils/datamodel/YangUnion.java b/src/main/java/org/onosproject/yangutils/datamodel/YangUnion.java
index c75068c..eb0e34d 100644
--- a/src/main/java/org/onosproject/yangutils/datamodel/YangUnion.java
+++ b/src/main/java/org/onosproject/yangutils/datamodel/YangUnion.java
@@ -18,7 +18,6 @@
 
 import java.util.LinkedList;
 import java.util.List;
-
 import org.onosproject.yangutils.datamodel.exceptions.DataModelException;
 import org.onosproject.yangutils.parser.Parsable;
 import org.onosproject.yangutils.utils.YangConstructType;
@@ -48,7 +47,7 @@
 /**
  * Represents data model node to maintain information defined in YANG union.
  */
-public class YangUnion extends YangNode implements Parsable {
+public class YangUnion extends YangNode implements Parsable, HasType {
 
     // List of YANG type.
     private List<YangType<?>> typeList;
@@ -68,11 +67,7 @@
         childUnionNumber = 1;
     }
 
-    /**
-     * Returns list of YANG type.
-     *
-     * @return the list of YANG type
-     */
+    @Override
     public List<YangType<?>> getTypeList() {
         return typeList;
     }
@@ -105,11 +100,11 @@
     }
 
     /**
-     * Add YANG type to type list.
+     * Adds YANG type to type list.
      *
      * @param yangType YANG type to be added to list
      * @throws DataModelException union member type must not be one of the
-     * built-in types "empty" or "leafref"
+     *                            built-in types "empty" or "leafref"
      */
     public void addType(YangType<?> yangType) throws DataModelException {
         if (yangType.getDataType() == YangDataTypes.EMPTY || yangType.getDataType() == YangDataTypes.LEAFREF) {
@@ -144,11 +139,21 @@
         return YangConstructType.UNION_DATA;
     }
 
+    /**
+     * Validates the data on entering the corresponding parse tree node.
+     *
+     * @throws DataModelException a violation of data model rules
+     */
     @Override
     public void validateDataOnEntry() throws DataModelException {
         //TODO: implement the method.
     }
 
+    /**
+     * Validates the data on exiting the corresponding parse tree node.
+     *
+     * @throws DataModelException a violation of data model rules
+     */
     @Override
     public void validateDataOnExit() throws DataModelException {
         //TODO: implement the method.
diff --git a/src/main/java/org/onosproject/yangutils/datamodel/utils/YangDataModelFactory.java b/src/main/java/org/onosproject/yangutils/datamodel/utils/YangDataModelFactory.java
index 03d82d1..110bd11 100644
--- a/src/main/java/org/onosproject/yangutils/datamodel/utils/YangDataModelFactory.java
+++ b/src/main/java/org/onosproject/yangutils/datamodel/utils/YangDataModelFactory.java
@@ -25,6 +25,7 @@
 import org.onosproject.yangutils.datamodel.YangModule;
 import org.onosproject.yangutils.datamodel.YangSubModule;
 import org.onosproject.yangutils.datamodel.YangTypeDef;
+import org.onosproject.yangutils.datamodel.YangUnion;
 import org.onosproject.yangutils.datamodel.YangUses;
 import org.onosproject.yangutils.datamodel.YangNotification;
 import org.onosproject.yangutils.datamodel.YangRpc;
@@ -40,6 +41,7 @@
 import org.onosproject.yangutils.translator.tojava.javamodel.YangJavaModule;
 import org.onosproject.yangutils.translator.tojava.javamodel.YangJavaSubModule;
 import org.onosproject.yangutils.translator.tojava.javamodel.YangJavaTypeDef;
+import org.onosproject.yangutils.translator.tojava.javamodel.YangJavaUnion;
 import org.onosproject.yangutils.translator.tojava.javamodel.YangJavaUses;
 import org.onosproject.yangutils.translator.tojava.javamodel.YangJavaNotification;
 import org.onosproject.yangutils.translator.tojava.javamodel.YangJavaRpc;
@@ -53,7 +55,7 @@
 public final class YangDataModelFactory {
 
     /**
-     * Utility class, hence private to prevent creating objects.
+     * Creates a YANG data model factory object.
      */
     private YangDataModelFactory() {
     }
@@ -224,7 +226,25 @@
      * Returns based on the target language generate the inherited data model node.
      *
      * @param targetLanguage target language in which YANG mapping needs to be
-     *            generated
+     *                       generated
+     * @return the corresponding inherited node based on the target language
+     */
+    public static YangUnion getYangUnionNode(GeneratedLanguage targetLanguage) {
+        switch (targetLanguage) {
+            case JAVA_GENERATION: {
+                return new YangJavaUnion();
+            }
+            default: {
+                throw new TranslatorException("Only YANG to Java is supported.");
+            }
+        }
+    }
+
+    /**
+     * Returns based on the target language generate the inherited data model node.
+     *
+     * @param targetLanguage target language in which YANG mapping needs to be
+     *                       generated
      * @return the corresponding inherited node based on the target language
      */
     public static YangUses getYangUsesNode(GeneratedLanguage targetLanguage) {
diff --git a/src/main/java/org/onosproject/yangutils/parser/impl/listeners/TypeListener.java b/src/main/java/org/onosproject/yangutils/parser/impl/listeners/TypeListener.java
index 416ce91..a2b4531 100644
--- a/src/main/java/org/onosproject/yangutils/parser/impl/listeners/TypeListener.java
+++ b/src/main/java/org/onosproject/yangutils/parser/impl/listeners/TypeListener.java
@@ -146,7 +146,7 @@
                  * in resolution list.
                  */
                 if (yangDataTypes == YangDataTypes.DERIVED) {
-                    // Parent YANG node of leaf to be added in resolution information.
+                    // Parent YANG node of leaf list to be added in resolution information.
                     Parsable leafListData = listener.getParsedDataStack().pop();
                     Parsable parentNodeOfLeafList = listener.getParsedDataStack().peek();
                     listener.getParsedDataStack().push(leafListData);
@@ -181,6 +181,26 @@
                     parserException.setCharPosition(ctx.getStart().getCharPositionInLine());
                     throw parserException;
                 }
+
+                /*
+                 * If data type is derived, resolution information to be added
+                 * in resolution list.
+                 */
+                if (yangDataTypes == YangDataTypes.DERIVED) {
+
+                    // Get the prefix information
+                    String prefix = ((YangType<?>) type).getPrefix();
+
+                    // Create empty derived info and attach it to type extended info.
+                    YangDerivedInfo<?> yangDerivedInfo = new YangDerivedInfo<>();
+                    ((YangType<YangDerivedInfo>) type).setDataTypeExtendedInfo(yangDerivedInfo);
+
+                    // Add resolution information to the list
+                    YangResolutionInfo resolutionInfo =
+                            new YangResolutionInfo<YangType>(type, (YangNode) unionNode, errorLine, errorPosition);
+                    addToResolutionList(resolutionInfo, ctx);
+                }
+
                 break;
             case TYPEDEF_DATA:
                 /* Prepare the base type info and set in derived type */
@@ -244,7 +264,7 @@
      * @param ctx context object of the grammar rule
      */
     private static void addToResolutionList(YangResolutionInfo<YangType> resolutionInfo,
-            GeneratedYangParser.TypeStatementContext ctx) {
+                                            GeneratedYangParser.TypeStatementContext ctx) {
         try {
             addResolutionInfo(resolutionInfo);
         } catch (DataModelException e) {
diff --git a/src/main/java/org/onosproject/yangutils/parser/impl/listeners/UnionListener.java b/src/main/java/org/onosproject/yangutils/parser/impl/listeners/UnionListener.java
index 5eeaa07..5a25762 100644
--- a/src/main/java/org/onosproject/yangutils/parser/impl/listeners/UnionListener.java
+++ b/src/main/java/org/onosproject/yangutils/parser/impl/listeners/UnionListener.java
@@ -53,6 +53,8 @@
 import org.onosproject.yangutils.parser.impl.TreeWalkListener;
 import org.onosproject.yangutils.utils.YangConstructType;
 
+import static org.onosproject.yangutils.datamodel.utils.GeneratedLanguage.JAVA_GENERATION;
+import static org.onosproject.yangutils.datamodel.utils.YangDataModelFactory.getYangUnionNode;
 import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.ENTRY;
 import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.EXIT;
 import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction.constructExtendedListenerErrorMessage;
@@ -96,7 +98,7 @@
         checkStackIsNotEmpty(listener, MISSING_HOLDER, UNION_DATA, "", ENTRY);
 
         if (listener.getParsedDataStack().peek() instanceof YangType) {
-            YangUnion unionNode = new YangUnion();
+            YangUnion unionNode = getYangUnionNode(JAVA_GENERATION);
             Parsable typeData = listener.getParsedDataStack().pop();
 
             // Check for stack to be non empty.
diff --git a/src/main/java/org/onosproject/yangutils/translator/tojava/GeneratedJavaFileType.java b/src/main/java/org/onosproject/yangutils/translator/tojava/GeneratedJavaFileType.java
index f23aec7..4be1a65 100644
--- a/src/main/java/org/onosproject/yangutils/translator/tojava/GeneratedJavaFileType.java
+++ b/src/main/java/org/onosproject/yangutils/translator/tojava/GeneratedJavaFileType.java
@@ -22,12 +22,6 @@
 public final class GeneratedJavaFileType {
 
     /**
-     * Creates an instance of generate java file type.
-     */
-    private GeneratedJavaFileType() {
-    }
-
-    /**
      * Interface file.
      */
     public static final int INTERFACE_MASK = 1;
@@ -56,4 +50,15 @@
      * Java class corresponding to typedef.
      */
     public static final int GENERATE_TYPEDEF_CLASS = 16;
+
+    /**
+     * Java class corresponding to union.
+     */
+    public static final int GENERATE_UNION_CLASS = 32;
+
+    /**
+     * Creates an instance of generate java file type.
+     */
+    private GeneratedJavaFileType() {
+    }
 }
diff --git a/src/main/java/org/onosproject/yangutils/translator/tojava/GeneratedTempFileType.java b/src/main/java/org/onosproject/yangutils/translator/tojava/GeneratedTempFileType.java
index 537ba47..ae22f07 100644
--- a/src/main/java/org/onosproject/yangutils/translator/tojava/GeneratedTempFileType.java
+++ b/src/main/java/org/onosproject/yangutils/translator/tojava/GeneratedTempFileType.java
@@ -22,53 +22,68 @@
 public final class GeneratedTempFileType {
 
     /**
-     * Creates an instance of generated temp file type.
-     */
-    private GeneratedTempFileType() {
-    }
-
-    /**
-     * attributes definition temporary file.
+     * Attributes definition temporary file.
      */
     public static final int ATTRIBUTES_MASK = 1;
 
     /**
-     * getter methods for interface.
+     * Getter methods for interface.
      */
     public static final int GETTER_FOR_INTERFACE_MASK = 2;
 
     /**
-     * getter methods for class.
+     * Getter methods for class.
      */
     public static final int GETTER_FOR_CLASS_MASK = 4;
 
     /**
-     * setter methods for interface.
+     * Setter methods for interface.
      */
     public static final int SETTER_FOR_INTERFACE_MASK = 8;
 
     /**
-     * setter methods for class.
+     * Setter methods for class.
      */
     public static final int SETTER_FOR_CLASS_MASK = 16;
 
     /**
-     * constructor method of class.
+     * Constructor method of class.
      */
     public static final int CONSTRUCTOR_IMPL_MASK = 32;
 
     /**
-     * hash code implementation of class.
+     * Hash code implementation of class.
      */
     public static final int HASH_CODE_IMPL_MASK = 64;
 
     /**
-     * equals implementation of class.
+     * Equals implementation of class.
      */
     public static final int EQUALS_IMPL_MASK = 128;
 
     /**
-     * to string implementation of class.
+     * To string implementation of class.
      */
     public static final int TO_STRING_IMPL_MASK = 256;
+
+    /**
+     * Of string implementation of class.
+     */
+    public static final int OF_STRING_IMPL_MASK = 512;
+
+    /**
+     * Constructor for type class like typedef, union.
+     */
+    public static final int CONSTRUCTOR_FOR_TYPE_MASK = 1024;
+
+    /**
+     * From string implementation of class.
+     */
+    public static final int UNION_FROM_STRING_IMPL_MASK = 2048;
+
+    /**
+     * Creates an instance of generated temp file type.
+     */
+    private GeneratedTempFileType() {
+    }
 }
diff --git a/src/main/java/org/onosproject/yangutils/translator/tojava/JavaAttributeInfo.java b/src/main/java/org/onosproject/yangutils/translator/tojava/JavaAttributeInfo.java
index b652f48..b02b4e2 100644
--- a/src/main/java/org/onosproject/yangutils/translator/tojava/JavaAttributeInfo.java
+++ b/src/main/java/org/onosproject/yangutils/translator/tojava/JavaAttributeInfo.java
@@ -21,8 +21,9 @@
 import org.onosproject.yangutils.translator.exception.TranslatorException;
 
 import static org.onosproject.yangutils.translator.tojava.JavaQualifiedTypeInfo.getIsQualifiedAccessOrAddToImportList;
+import static org.onosproject.yangutils.translator.tojava.JavaQualifiedTypeInfo.getQualifiedInfoOfFromString;
+import static org.onosproject.yangutils.translator.tojava.JavaQualifiedTypeInfo.getQualifiedTypeInfoOfAttribute;
 import static org.onosproject.yangutils.translator.tojava.JavaQualifiedTypeInfo.getQualifiedTypeInfoOfCurNode;
-import static org.onosproject.yangutils.translator.tojava.JavaQualifiedTypeInfo.getQualifiedTypeInfoOfLeafAttribute;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getCamelCase;
 
 /**
@@ -65,9 +66,9 @@
     /**
      * Creates object of java attribute info.
      *
-     * @param attrType YANG type
-     * @param name attribute name
-     * @param isListAttr is list attribute
+     * @param attrType        YANG type
+     * @param name            attribute name
+     * @param isListAttr      is list attribute
      * @param isQualifiedName is qualified name
      */
     public JavaAttributeInfo(YangType<?> attrType, String name, boolean isListAttr, boolean isQualifiedName) {
@@ -78,6 +79,51 @@
     }
 
     /**
+     * Creates an attribute info object corresponding to the passed type's attribute
+     * information and return it.
+     *
+     * @param curNode               current data model node for which the java file is being generated
+     * @param referredTypesAttrInfo attribute of referred type
+     * @return JavaAttributeInfo attribute details required to add in temporary files
+     */
+    public static JavaAttributeInfo getFromStringAttributeInfo(YangNode curNode,
+                                                               JavaAttributeInfo referredTypesAttrInfo) {
+
+        JavaQualifiedTypeInfo qualifiedInfoOfFromString = getQualifiedInfoOfFromString(referredTypesAttrInfo);
+        /*
+         * Create a new java attribute info with qualified information of
+         * wrapper classes.
+         */
+        return getAttributeInfoForTheData(qualifiedInfoOfFromString, referredTypesAttrInfo.getAttributeName(),
+                referredTypesAttrInfo.getAttributeType(), curNode, false);
+    }
+
+    /**
+     * Creates an attribute info object corresponding to the passed type attribute
+     * information and return it.
+     *
+     * @param curNode         current data model node for which the java file is being
+     *                        generated
+     * @param attributeType   leaf data type
+     * @param attributeName   leaf name
+     * @param isListAttribute is the current added attribute needs to be a list
+     * @return AttributeInfo attribute details required to add in temporary
+     * files
+     */
+    public static JavaAttributeInfo getAttributeInfoOfType(YangNode curNode,
+                                                           YangType<?> attributeType, String attributeName,
+                                                           boolean isListAttribute) {
+        /*
+         * Get the import info corresponding to the attribute for import in
+         * generated java files or qualified access
+         */
+        JavaQualifiedTypeInfo importInfo = getQualifiedTypeInfoOfAttribute(curNode,
+                attributeType, attributeName, isListAttribute);
+
+        return getAttributeInfoForTheData(importInfo, attributeName, attributeType, curNode, isListAttribute);
+    }
+
+    /**
      * Returns the data type info of attribute.
      *
      * @return the data type info of attribute
@@ -144,7 +190,7 @@
      * manner.
      *
      * @return the if the added attribute has to be accessed in a fully
-     *         qualified manner.
+     * qualified manner.
      */
     public boolean isQualifiedName() {
         return isQualifiedName;
@@ -155,7 +201,7 @@
      * manner.
      *
      * @param isQualified if the added attribute has to be accessed in a fully
-     *            qualified manner
+     *                    qualified manner
      */
     public void setIsQualifiedAccess(boolean isQualified) {
         isQualifiedName = isQualified;
@@ -184,23 +230,23 @@
      * Creates an attribute info object corresponding to the passed leaf
      * information and return it.
      *
-     * @param curNode current data model node for which the java file is being
-     *            generated
-     * @param attributeType leaf data type
-     * @param attributeName leaf name
+     * @param curNode         current data model node for which the java file is being
+     *                        generated
+     * @param attributeType   leaf data type
+     * @param attributeName   leaf name
      * @param isListAttribute is the current added attribute needs to be a list
      * @return AttributeInfo attribute details required to add in temporary
-     *         files
+     * files
      */
     public static JavaAttributeInfo getAttributeInfoOfLeaf(YangNode curNode,
-            YangType<?> attributeType, String attributeName,
-            boolean isListAttribute) {
+                                                           YangType<?> attributeType, String attributeName,
+                                                           boolean isListAttribute) {
 
         /*
          * Get the import info corresponding to the attribute for import in
          * generated java files or qualified access
          */
-        JavaQualifiedTypeInfo importInfo = getQualifiedTypeInfoOfLeafAttribute(curNode,
+        JavaQualifiedTypeInfo importInfo = getQualifiedTypeInfoOfAttribute(curNode,
                 attributeType, attributeName, isListAttribute);
 
         return getAttributeInfoForTheData(importInfo, attributeName, attributeType, curNode, isListAttribute);
@@ -210,12 +256,12 @@
      * Creates an attribute info object corresponding to a data model node and
      * return it.
      *
-     * @param curNode current data model node for which the java code generation
-     *            is being handled
+     * @param curNode    current data model node for which the java code generation
+     *                   is being handled
      * @param parentNode parent node in which the current node is an attribute
      * @param isListNode is the current added attribute needs to be a list
      * @return AttributeInfo attribute details required to add in temporary
-     *         files
+     * files
      */
     public static JavaAttributeInfo getCurNodeAsAttributeInParent(
             YangNode curNode, YangNode parentNode, boolean isListNode) {
@@ -233,43 +279,18 @@
     }
 
     /**
-     * Creates an attribute info object corresponding to the passed type def attribute
-     * information and return it.
-     *
-     * @param curNode current data model node for which the java file is being
-     *            generated
-     * @param attributeType leaf data type
-     * @param attributeName leaf name
-     * @param isListAttribute is the current added attribute needs to be a list
-     * @return AttributeInfo attribute details required to add in temporary
-     *         files
-     */
-    public static JavaAttributeInfo getAttributeInfoOfTypeDef(YangNode curNode,
-            YangType<?> attributeType, String attributeName,
-            boolean isListAttribute) {
-
-        /*
-         * Get the import info corresponding to the attribute for import in
-         * generated java files or qualified access
-         */
-        JavaQualifiedTypeInfo importInfo = getQualifiedTypeInfoOfLeafAttribute(curNode,
-                attributeType, attributeName, isListAttribute);
-
-        return getAttributeInfoForTheData(importInfo, attributeName, attributeType, curNode, isListAttribute);
-    }
-
-    /**
      * Returns java attribute info.
      *
-     * @param importInfo java qualified type info
-     * @param attributeName attribute name
-     * @param attributeType attribute type
-     * @param curNode current YANG node
+     * @param importInfo      java qualified type info
+     * @param attributeName   attribute name
+     * @param attributeType   attribute type
+     * @param curNode         current YANG node
      * @param isListAttribute is list attribute
      * @return java attribute info.
      */
     private static JavaAttributeInfo getAttributeInfoForTheData(JavaQualifiedTypeInfo importInfo, String attributeName,
-            YangType<?> attributeType, YangNode curNode, boolean isListAttribute) {
+                                                                YangType<?> attributeType, YangNode curNode,
+                                                                boolean isListAttribute) {
 
         JavaAttributeInfo newAttr = new JavaAttributeInfo();
         newAttr.setImportInfo(importInfo);
diff --git a/src/main/java/org/onosproject/yangutils/translator/tojava/JavaQualifiedTypeInfo.java b/src/main/java/org/onosproject/yangutils/translator/tojava/JavaQualifiedTypeInfo.java
index 70aab37..cc73ad4 100644
--- a/src/main/java/org/onosproject/yangutils/translator/tojava/JavaQualifiedTypeInfo.java
+++ b/src/main/java/org/onosproject/yangutils/translator/tojava/JavaQualifiedTypeInfo.java
@@ -17,14 +17,15 @@
 package org.onosproject.yangutils.translator.tojava;
 
 import java.util.Objects;
-
 import org.onosproject.yangutils.datamodel.YangNode;
 import org.onosproject.yangutils.datamodel.YangType;
 import org.onosproject.yangutils.translator.exception.TranslatorException;
 import org.onosproject.yangutils.translator.tojava.utils.AttributesJavaDataType;
-
 import com.google.common.base.MoreObjects;
 
+import static org.onosproject.yangutils.translator.tojava.utils.AttributesJavaDataType.getJavaImportClass;
+import static org.onosproject.yangutils.translator.tojava.utils.AttributesJavaDataType.getJavaImportPackage;
+
 /**
  * Represents the information about individual imports in the generated file.
  */
@@ -86,18 +87,18 @@
      * Returns the import info for an attribute, which needs to be used for code
      * generation for import or for qualified access.
      *
-     * @param curNode current data model node for which the java file is being
-     *            generated
-     * @param attrType type of attribute being added, it will be null, when the
-     *            child class is added as an attribute
+     * @param curNode       current data model node for which the java file is being
+     *                      generated
+     * @param attrType      type of attribute being added, it will be null, when the
+     *                      child class is added as an attribute
      * @param attributeName name of the attribute being added, it will used in
-     *            import info for child class
-     * @param isListAttr is the added attribute going to be used as a list
+     *                      import info for child class
+     * @param isListAttr    is the added attribute going to be used as a list
      * @return return the import info for this attribute
      */
-    public static JavaQualifiedTypeInfo getQualifiedTypeInfoOfLeafAttribute(YangNode curNode,
-            YangType<?> attrType, String attributeName,
-            boolean isListAttr) {
+    public static JavaQualifiedTypeInfo getQualifiedTypeInfoOfAttribute(YangNode curNode,
+                                                                        YangType<?> attrType, String attributeName,
+                                                                        boolean isListAttr) {
 
         JavaQualifiedTypeInfo importInfo = new JavaQualifiedTypeInfo();
 
@@ -139,15 +140,15 @@
      * Returns the import info for an attribute, which needs to be used for code
      * generation for import or for qualified access.
      *
-     * @param curNode current data model node for which the java file is being
-     *            generated
+     * @param curNode       current data model node for which the java file is being
+     *                      generated
      * @param attributeName name of the attribute being added, it will used in
-     *            import info for child class
-     * @param isListAttr is the added attribute going to be used as a list
+     *                      import info for child class
+     * @param isListAttr    is the added attribute going to be used as a list
      * @return return the import info for this attribute
      */
     public static JavaQualifiedTypeInfo getQualifiedTypeInfoOfCurNode(YangNode curNode,
-            String attributeName, boolean isListAttr) {
+                                                                      String attributeName, boolean isListAttr) {
 
         JavaQualifiedTypeInfo importInfo = new JavaQualifiedTypeInfo();
 
@@ -168,16 +169,35 @@
     }
 
     /**
+     * Get the java qualified type information for the wrapper classes.
+     *
+     * @param referredTypesAttrInfo attribute of referred type
+     * @return return the import info for this attribute
+     */
+    public static JavaQualifiedTypeInfo getQualifiedInfoOfFromString(JavaAttributeInfo referredTypesAttrInfo) {
+        /*
+         * Get the java qualified type information for the wrapper classes and
+         * set it in new java attribute information.
+         */
+        JavaQualifiedTypeInfo qualifiedInfoOfFromString = new JavaQualifiedTypeInfo();
+        qualifiedInfoOfFromString.setClassInfo(
+                getJavaImportClass(referredTypesAttrInfo.getAttributeType(), true));
+        qualifiedInfoOfFromString.setPkgInfo(
+                getJavaImportPackage(referredTypesAttrInfo.getAttributeType(), true, null));
+        return qualifiedInfoOfFromString;
+    }
+
+    /**
      * Returns if the attribute needs to be accessed in a qualified manner or not,
      * if it needs to be imported, then the same needs to be done.
      *
-     * @param curNode current cache of the data model node for which java file
-     *            is bing generated
+     * @param curNode    current cache of the data model node for which java file
+     *                   is bing generated
      * @param importInfo import info for the current attribute being added
      * @return status of the qualified access to the attribute
      */
     public static boolean getIsQualifiedAccessOrAddToImportList(YangNode curNode,
-            JavaQualifiedTypeInfo importInfo) {
+                                                                JavaQualifiedTypeInfo importInfo) {
 
         boolean isImportPkgEqualCurNodePkg;
         if (!(curNode instanceof HasJavaFileInfo)) {
@@ -229,10 +249,10 @@
      * Checks if the import info is same as the package of the current generated
      * java file.
      *
-     * @param curNode Java identifier of the current data model node
+     * @param curNode    Java identifier of the current data model node
      * @param importInfo import info for an attribute
      * @return true if the import info is same as the current nodes package
-     *         false otherwise
+     * false otherwise
      */
     public static boolean isImportPkgEqualCurNodePkg(
             YangNode curNode, JavaQualifiedTypeInfo importInfo) {
diff --git a/src/main/java/org/onosproject/yangutils/translator/tojava/TempJavaCodeFragmentFiles.java b/src/main/java/org/onosproject/yangutils/translator/tojava/TempJavaCodeFragmentFiles.java
index 06c08d7..b66e253 100644
--- a/src/main/java/org/onosproject/yangutils/translator/tojava/TempJavaCodeFragmentFiles.java
+++ b/src/main/java/org/onosproject/yangutils/translator/tojava/TempJavaCodeFragmentFiles.java
@@ -20,31 +20,36 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
-
+import org.onosproject.yangutils.datamodel.HasType;
 import org.onosproject.yangutils.datamodel.YangLeaf;
 import org.onosproject.yangutils.datamodel.YangLeafList;
 import org.onosproject.yangutils.datamodel.YangLeavesHolder;
 import org.onosproject.yangutils.datamodel.YangNode;
-import org.onosproject.yangutils.datamodel.YangTypeDef;
+import org.onosproject.yangutils.datamodel.YangType;
 import org.onosproject.yangutils.translator.exception.TranslatorException;
 
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.BUILDER_CLASS_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.BUILDER_INTERFACE_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.GENERATE_TYPEDEF_CLASS;
+import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.GENERATE_UNION_CLASS;
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.IMPL_CLASS_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.INTERFACE_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.ATTRIBUTES_MASK;
+import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.CONSTRUCTOR_FOR_TYPE_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.CONSTRUCTOR_IMPL_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.EQUALS_IMPL_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.GETTER_FOR_CLASS_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.GETTER_FOR_INTERFACE_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.HASH_CODE_IMPL_MASK;
+import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.OF_STRING_IMPL_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.SETTER_FOR_CLASS_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.SETTER_FOR_INTERFACE_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.TO_STRING_IMPL_MASK;
+import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.UNION_FROM_STRING_IMPL_MASK;
 import static org.onosproject.yangutils.translator.tojava.JavaAttributeInfo.getAttributeInfoOfLeaf;
-import static org.onosproject.yangutils.translator.tojava.JavaAttributeInfo.getAttributeInfoOfTypeDef;
+import static org.onosproject.yangutils.translator.tojava.JavaAttributeInfo.getAttributeInfoOfType;
 import static org.onosproject.yangutils.translator.tojava.JavaAttributeInfo.getCurNodeAsAttributeInParent;
+import static org.onosproject.yangutils.translator.tojava.JavaAttributeInfo.getFromStringAttributeInfo;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaCodeSnippetGen.getJavaAttributeDefination;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaCodeSnippetGen.getJavaClassDefClose;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaFileGenerator.generateBuilderClassFile;
@@ -52,6 +57,7 @@
 import static org.onosproject.yangutils.translator.tojava.utils.JavaFileGenerator.generateImplClassFile;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaFileGenerator.generateInterfaceFile;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaFileGenerator.generateTypeDefClassFile;
+import static org.onosproject.yangutils.translator.tojava.utils.JavaFileGenerator.generateUnionClassFile;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaFileGeneratorUtils.getFileObject;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getCamelCase;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getCaptialCase;
@@ -62,16 +68,17 @@
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getConstructor;
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getDefaultConstructorString;
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getEqualsMethod;
+import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getFromStringMethod;
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getGetterForClass;
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getGetterString;
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getHashCodeMethod;
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getOfMethod;
+import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getOfMethodStringAndJavaDoc;
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getOverRideString;
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getSetterForClass;
-import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getSetterForTypeDefClass;
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getSetterString;
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getToStringMethod;
-import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getTypeDefConstructor;
+import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getTypeConstructorStringAndJavaDoc;
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.parseBuilderInterfaceBuildMethodString;
 import static org.onosproject.yangutils.translator.tojava.utils.TempJavaCodeFragmentFilesUtils.addArrayListImport;
 import static org.onosproject.yangutils.translator.tojava.utils.TempJavaCodeFragmentFilesUtils.addAugmentedInfoImport;
@@ -91,11 +98,9 @@
 import static org.onosproject.yangutils.utils.UtilConstants.SLASH;
 import static org.onosproject.yangutils.utils.io.impl.FileSystemUtil.createPackage;
 import static org.onosproject.yangutils.utils.io.impl.FileSystemUtil.readAppendFile;
-import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.getJavaDoc;
 import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.JavaDocType.GETTER_METHOD;
 import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.JavaDocType.OF_METHOD;
-import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.JavaDocType.TYPE_DEF_CONSTRUCTOR;
-import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.JavaDocType.TYPE_DEF_SETTER_METHOD;
+import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.getJavaDoc;
 import static org.onosproject.yangutils.utils.io.impl.YangIoUtils.clean;
 import static org.onosproject.yangutils.utils.io.impl.YangIoUtils.insertDataIntoJavaFile;
 import static org.onosproject.yangutils.utils.io.impl.YangIoUtils.mergeJavaFiles;
@@ -193,6 +198,21 @@
     private static final String EQUALS_METHOD_FILE_NAME = "Equals";
 
     /**
+     * File name for of string method.
+     */
+    private static final String OF_STRING_METHOD_FILE_NAME = "OfString";
+
+    /**
+     * File name for construction for special type like union, typedef.
+     */
+    private static final String CONSTRUCTOR_FOR_TYPE_FILE_NAME = "ConstructorForType";
+
+    /**
+     * File name for from string method.
+     */
+    private static final String UNION_FROM_STRING_METHOD_FILE_NAME = "UnionFromString";
+
+    /**
      * File name for interface java file name suffix.
      */
     private static final String INTERFACE_FILE_NAME_SUFFIX = EMPTY_STRING;
@@ -218,6 +238,11 @@
     private static final String TYPEDEF_CLASS_FILE_NAME_SUFFIX = EMPTY_STRING;
 
     /**
+     * File name for generated class file for special type like union, typedef suffix.
+     */
+    private static final String UNION_TYPE_CLASS_FILE_NAME_SUFFIX = EMPTY_STRING;
+
+    /**
      * Java file handle for interface file.
      */
     private File interfaceJavaFileHandle;
@@ -243,6 +268,11 @@
     private File typedefClassJavaFileHandle;
 
     /**
+     * Java file handle for type class like union, typedef file.
+     */
+    private File typeClassJavaFileHandle;
+
+    /**
      * Temporary file handle for attribute.
      */
     private File attributesTempFileHandle;
@@ -288,6 +318,21 @@
     private File toStringImplTempFileHandle;
 
     /**
+     * Temporary file handle for of string method of class.
+     */
+    private File ofStringImplTempFileHandle;
+
+    /**
+     * Temporary file handle for constructor for type class.
+     */
+    private File constructorForTypeTempFileHandle;
+
+    /**
+     * Temporary file handle for union's from string method of class.
+     */
+    private File unionFromStringImplTempFileHandle;
+
+    /**
      * Java attribute info.
      */
     private JavaAttributeInfo newAttrInfo;
@@ -306,8 +351,8 @@
      * Creates an instance of temporary java code fragment.
      *
      * @param genFileType file generation type
-     * @param genDir file generation directory
-     * @param className class name
+     * @param genDir      file generation directory
+     * @param className   class name
      * @throws IOException when fails to create new file handle
      */
     public TempJavaCodeFragmentFiles(int genFileType, String genDir, String className)
@@ -368,6 +413,24 @@
             generatedTempFiles |= HASH_CODE_IMPL_MASK;
             generatedTempFiles |= EQUALS_IMPL_MASK;
             generatedTempFiles |= TO_STRING_IMPL_MASK;
+            generatedTempFiles |= OF_STRING_IMPL_MASK;
+            generatedTempFiles |= CONSTRUCTOR_FOR_TYPE_MASK;
+        }
+
+        /**
+         * Initialize getterImpl, attributes, hash code, equals, of string,
+         * constructor, union's to string, union's from string when generation
+         * file type matches to union class mask.
+         */
+        if ((genFileType & GENERATE_UNION_CLASS) != 0) {
+            generatedTempFiles |= ATTRIBUTES_MASK;
+            generatedTempFiles |= GETTER_FOR_CLASS_MASK;
+            generatedTempFiles |= HASH_CODE_IMPL_MASK;
+            generatedTempFiles |= EQUALS_IMPL_MASK;
+            generatedTempFiles |= OF_STRING_IMPL_MASK;
+            generatedTempFiles |= CONSTRUCTOR_FOR_TYPE_MASK;
+            generatedTempFiles |= TO_STRING_IMPL_MASK;
+            generatedTempFiles |= UNION_FROM_STRING_IMPL_MASK;
         }
 
         if ((generatedTempFiles & ATTRIBUTES_MASK) != 0) {
@@ -404,6 +467,18 @@
         if ((generatedTempFiles & TO_STRING_IMPL_MASK) != 0) {
             setToStringImplTempFileHandle(getTemporaryFileHandle(TO_STRING_METHOD_FILE_NAME));
         }
+
+        if ((generatedTempFiles & OF_STRING_IMPL_MASK) != 0) {
+            setOfStringImplTempFileHandle(getTemporaryFileHandle(OF_STRING_METHOD_FILE_NAME));
+        }
+
+        if ((generatedTempFiles & CONSTRUCTOR_FOR_TYPE_MASK) != 0) {
+            setConstructorForTypeTempFileHandle(getTemporaryFileHandle(CONSTRUCTOR_FOR_TYPE_FILE_NAME));
+        }
+
+        if ((generatedTempFiles & UNION_FROM_STRING_IMPL_MASK) != 0) {
+            setUnionFromStringImplTempFileHandle(getTemporaryFileHandle(UNION_FROM_STRING_METHOD_FILE_NAME));
+        }
     }
 
     /**
@@ -497,6 +572,24 @@
     }
 
     /**
+     * Returns java file handle for type class file.
+     *
+     * @return java file handle for type class file
+     */
+    private File getTypeClassJavaFileHandle() {
+        return typeClassJavaFileHandle;
+    }
+
+    /**
+     * Sets the java file handle for type class file.
+     *
+     * @param typeClassJavaFileHandle type file handle
+     */
+    private void setTypeClassJavaFileHandle(File typeClassJavaFileHandle) {
+        this.typeClassJavaFileHandle = typeClassJavaFileHandle;
+    }
+
+    /**
      * Returns attribute's temporary file handle.
      *
      * @return temporary file handle
@@ -659,6 +752,60 @@
     }
 
     /**
+     * Returns of string method's temporary file handle.
+     *
+     * @return of string method's temporary file handle
+     */
+    public File getOfStringImplTempFileHandle() {
+        return ofStringImplTempFileHandle;
+    }
+
+    /**
+     * Set of string method's temporary file handle.
+     *
+     * @param ofStringImplTempFileHandle of string method's temporary file handle
+     */
+    private void setOfStringImplTempFileHandle(File ofStringImplTempFileHandle) {
+        this.ofStringImplTempFileHandle = ofStringImplTempFileHandle;
+    }
+
+    /**
+     * Returns type class constructor method's temporary file handle.
+     *
+     * @return type class constructor method's temporary file handle
+     */
+    public File getConstructorForTypeTempFileHandle() {
+        return constructorForTypeTempFileHandle;
+    }
+
+    /**
+     * Sets type class constructor method's temporary file handle.
+     *
+     * @param constructorForTypeTempFileHandle type class constructor method's temporary file handle
+     */
+    private void setConstructorForTypeTempFileHandle(File constructorForTypeTempFileHandle) {
+        this.constructorForTypeTempFileHandle = constructorForTypeTempFileHandle;
+    }
+
+    /**
+     * Returns union's from string method's temporary file handle.
+     *
+     * @return union's from string method's temporary file handle
+     */
+    public File getUnionFromStringImplTempFileHandle() {
+        return unionFromStringImplTempFileHandle;
+    }
+
+    /**
+     * Sets union's from string method's temporary file handle.
+     *
+     * @param unionFromStringImplTempFileHandle union's from string method's temporary file handle
+     */
+    private void setUnionFromStringImplTempFileHandle(File unionFromStringImplTempFileHandle) {
+        this.unionFromStringImplTempFileHandle = unionFromStringImplTempFileHandle;
+    }
+
+    /**
      * Returns java attribute info.
      *
      * @return java attribute info
@@ -727,6 +874,28 @@
     }
 
     /**
+     * Adds of string for type.
+     *
+     * @param attr attribute info
+     * @throws IOException when fails to append to temporary file
+     */
+    private void addOfStringMethod(JavaAttributeInfo attr) throws IOException {
+        appendToFile(getOfStringImplTempFileHandle(), getOfMethodStringAndJavaDoc(attr, generatedJavaClassName)
+                + NEW_LINE);
+    }
+
+    /**
+     * Adds type constructor.
+     *
+     * @param attr attribute info
+     * @throws IOException when fails to append to temporary file
+     */
+    private void addTypeConstructor(JavaAttributeInfo attr) throws IOException {
+        appendToFile(getConstructorForTypeTempFileHandle(), getTypeConstructorStringAndJavaDoc(attr,
+                generatedJavaClassName) + NEW_LINE);
+    }
+
+    /**
      * Adds attribute for class.
      *
      * @param attr attribute info
@@ -749,7 +918,7 @@
     /**
      * Adds getter method's impl for class.
      *
-     * @param attr attribute info
+     * @param attr        attribute info
      * @param genFiletype generated file type
      * @throws IOException when fails to append to temporary file
      */
@@ -828,28 +997,6 @@
     }
 
     /**
-     * Adds typedef constructor for class.
-     *
-     * @return typedef constructor for class
-     * @throws IOException when fails to append to file
-     */
-    public String addTypeDefConstructor() throws IOException {
-        return NEW_LINE + getJavaDoc(TYPE_DEF_CONSTRUCTOR, generatedJavaClassName, false)
-                + getTypeDefConstructor(newAttrInfo, generatedJavaClassName) + NEW_LINE;
-    }
-
-    /**
-     * Adds default constructor for class.
-     *
-     * @return default constructor for class
-     * @throws IOException when fails to append to file
-     */
-    public String addTypeDefsSetter() throws IOException {
-        return getJavaDoc(TYPE_DEF_SETTER_METHOD, generatedJavaClassName, false) + getSetterForTypeDefClass(newAttrInfo)
-                + NEW_LINE;
-    }
-
-    /**
      * Adds default constructor for class.
      *
      * @return default constructor for class
@@ -891,6 +1038,19 @@
     }
 
     /**
+     * Add from string method for union class.
+     *
+     * @param javaAttributeInfo       type attribute info
+     * @param fromStringAttributeInfo from string attribute info
+     * @throws IOException when fails to append to temporary file
+     */
+    private void addUnionFromStringMethod(JavaAttributeInfo javaAttributeInfo,
+                                          JavaAttributeInfo fromStringAttributeInfo) throws IOException {
+        appendToFile(getUnionFromStringImplTempFileHandle(), getFromStringMethod(javaAttributeInfo,
+                fromStringAttributeInfo) + NEW_LINE);
+    }
+
+    /**
      * Returns a temporary file handle for the specific file type.
      *
      * @param fileName file name
@@ -993,12 +1153,12 @@
      * Adds current node info as and attribute to the parent generated file.
      *
      * @param curNode current node which needs to be added as an attribute in
-     *            the parent generated code
-     * @param isList is list construct
+     *                the parent generated code
+     * @param isList  is list construct
      * @throws IOException IO operation exception
      */
     public void addCurNodeInfoInParentTempFile(YangNode curNode,
-            boolean isList) throws IOException {
+                                               boolean isList) throws IOException {
 
         YangNode parent = getParentNodeInGenCode(curNode);
         if (!(parent instanceof JavaCodeGenerator)) {
@@ -1019,11 +1179,11 @@
      * Adds leaf attributes in generated files.
      *
      * @param listOfLeaves list of YANG leaf
-     * @param curNode current data model node
+     * @param curNode      current data model node
      * @throws IOException IO operation fail
      */
     private void addLeavesInfoToTempFiles(List<YangLeaf> listOfLeaves,
-            YangNode curNode) throws IOException {
+                                          YangNode curNode) throws IOException {
 
         if (listOfLeaves != null) {
             for (YangLeaf leaf : listOfLeaves) {
@@ -1039,11 +1199,11 @@
      * Adds leaf list's attributes in generated files.
      *
      * @param listOfLeafList list of YANG leaves
-     * @param curNode cached file handle
+     * @param curNode        cached file handle
      * @throws IOException IO operation fail
      */
     private void addLeafListInfoToTempFiles(List<YangLeafList> listOfLeafList,
-            YangNode curNode) throws IOException {
+                                            YangNode curNode) throws IOException {
 
         if (listOfLeafList != null) {
 
@@ -1087,16 +1247,45 @@
     }
 
     /**
-     * Adds leaf attributes in generated files.
+     * Add all the type in the current data model node as part of the
+     * generated temporary file.
      *
-     * @param curNode current data model node
+     * @param hasType YANG java data model node which has type info, eg union / typedef
      * @throws IOException IO operation fail
      */
-    public void addTypeDefAttributeToTempFiles(YangNode curNode) throws IOException {
+    public void addTypeInfoToTempFiles(HasType hasType) throws IOException {
 
-        JavaAttributeInfo javaAttributeInfo = getAttributeInfoOfTypeDef(curNode,
-                ((YangTypeDef) curNode).getTypeDefBaseType(),
-                ((YangTypeDef) curNode).getName(), false);
+        List<YangType<?>> typeList = hasType.getTypeList();
+        if (typeList != null) {
+            for (YangType<?> yangType : typeList) {
+                JavaAttributeInfo javaAttributeInfo = getAttributeInfoOfType((YangNode) hasType,
+                        yangType, getTypeName(yangType.getDataTypeName()), false);
+                addJavaSnippetInfoToApplicableTempFiles((YangNode) hasType, javaAttributeInfo);
+            }
+        }
+    }
+
+    private String getTypeName(String dataTypeName) {
+        return dataTypeName;
+        //TODO: implement the method.
+    }
+
+    /**
+     * Adds the new attribute info to the target generated temporary files for union class.
+     *
+     * @param hasType           the node for which the type is being added as an attribute
+     * @param javaAttributeInfo the attribute info that needs to be added to temporary
+     *                          files
+     * @throws IOException IO operation fail
+     */
+    private void addJavaSnippetInfoToApplicableTempFiles(YangNode hasType, JavaAttributeInfo javaAttributeInfo)
+            throws IOException {
+
+        JavaAttributeInfo fromStringAttributeInfo = getFromStringAttributeInfo(hasType, javaAttributeInfo);
+
+        if ((generatedTempFiles & UNION_FROM_STRING_IMPL_MASK) != 0) {
+            addUnionFromStringMethod(javaAttributeInfo, fromStringAttributeInfo);
+        }
         addJavaSnippetInfoToApplicableTempFiles(javaAttributeInfo);
     }
 
@@ -1104,7 +1293,7 @@
      * Adds the new attribute info to the target generated temporary files.
      *
      * @param newAttrInfo the attribute info that needs to be added to temporary
-     *            files
+     *                    files
      * @throws IOException IO operation fail
      */
     void addJavaSnippetInfoToApplicableTempFiles(JavaAttributeInfo newAttrInfo)
@@ -1147,6 +1336,15 @@
             if ((generatedTempFiles & TO_STRING_IMPL_MASK) != 0) {
                 addToStringMethod(newAttrInfo);
             }
+
+            if ((generatedTempFiles & OF_STRING_IMPL_MASK) != 0) {
+                addOfStringMethod(newAttrInfo);
+            }
+
+            if ((generatedTempFiles & CONSTRUCTOR_FOR_TYPE_MASK) != 0) {
+                addTypeConstructor(newAttrInfo);
+            }
+
         }
     }
 
@@ -1182,7 +1380,7 @@
      * Constructs java code exit.
      *
      * @param fileType generated file type
-     * @param curNode current YANG node
+     * @param curNode  current YANG node
      * @throws IOException when fails to generate java files
      */
     public void generateJavaFile(int fileType, YangNode curNode) throws IOException {
@@ -1285,6 +1483,15 @@
         }
 
         /**
+         * Creates type class file.
+         */
+        if ((fileType & GENERATE_UNION_CLASS) != 0) {
+            addImportsToStringAndHasCodeMethods(curNode, imports);
+            setTypeClassJavaFileHandle(getJavaFileHandle(getJavaClassName(UNION_TYPE_CLASS_FILE_NAME_SUFFIX)));
+            setTypeClassJavaFileHandle(generateUnionClassFile(getTypeClassJavaFileHandle(), curNode, imports));
+        }
+
+        /**
          * Close all the file handles.
          */
         close(false);
@@ -1294,8 +1501,7 @@
      * Removes all temporary file handles.
      *
      * @param isErrorOccurred when translator fails to generate java files we need to close
-     * all open file handles include temporary files and java files.
-     *
+     *                        all open file handles include temporary files and java files.
      * @throws IOException when failed to delete the temporary files
      */
     public void close(boolean isErrorOccurred) throws IOException {
@@ -1319,6 +1525,9 @@
         if ((generatedJavaFiles & GENERATE_TYPEDEF_CLASS) != 0) {
             closeFile(getTypedefClassJavaFileHandle(), isError);
         }
+        if ((generatedJavaFiles & GENERATE_UNION_CLASS) != 0) {
+            closeFile(getTypeClassJavaFileHandle(), isError);
+        }
 
         /**
          * Close all temporary file handles and delete the files.
@@ -1350,7 +1559,15 @@
         if ((generatedTempFiles & EQUALS_IMPL_MASK) != 0) {
             closeFile(getEqualsImplTempFileHandle(), true);
         }
-
+        if ((generatedTempFiles & CONSTRUCTOR_FOR_TYPE_MASK) != 0) {
+            closeFile(getConstructorForTypeTempFileHandle(), true);
+        }
+        if ((generatedTempFiles & OF_STRING_IMPL_MASK) != 0) {
+            closeFile(getOfStringImplTempFileHandle(), true);
+        }
+        if ((generatedTempFiles & UNION_FROM_STRING_IMPL_MASK) != 0) {
+            closeFile(getUnionFromStringImplTempFileHandle(), true);
+        }
         clean(getTempDirPath());
         generatedTempFiles = 0;
     }
diff --git a/src/main/java/org/onosproject/yangutils/translator/tojava/javamodel/YangJavaTypeDef.java b/src/main/java/org/onosproject/yangutils/translator/tojava/javamodel/YangJavaTypeDef.java
index 3e4a202..7e32f08 100644
--- a/src/main/java/org/onosproject/yangutils/translator/tojava/javamodel/YangJavaTypeDef.java
+++ b/src/main/java/org/onosproject/yangutils/translator/tojava/javamodel/YangJavaTypeDef.java
@@ -16,12 +16,8 @@
 package org.onosproject.yangutils.translator.tojava.javamodel;
 
 import java.io.IOException;
-
 import org.onosproject.yangutils.datamodel.YangTypeDef;
 import org.onosproject.yangutils.translator.exception.TranslatorException;
-import org.onosproject.yangutils.translator.tojava.HasJavaFileInfo;
-import org.onosproject.yangutils.translator.tojava.HasJavaImportData;
-import org.onosproject.yangutils.translator.tojava.HasTempJavaCodeFragmentFiles;
 import org.onosproject.yangutils.translator.tojava.JavaCodeGenerator;
 import org.onosproject.yangutils.translator.tojava.JavaFileInfo;
 import org.onosproject.yangutils.translator.tojava.JavaImportData;
@@ -29,17 +25,12 @@
 import org.onosproject.yangutils.translator.tojava.utils.YangPluginConfig;
 
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.GENERATE_TYPEDEF_CLASS;
-import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getCamelCase;
-import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getCaptialCase;
-import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getCurNodePackage;
-import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getPackageDirPathFromJavaJPackage;
-import static org.onosproject.yangutils.utils.io.impl.YangIoUtils.getAbsolutePackagePath;
+import static org.onosproject.yangutils.translator.tojava.utils.YangJavaModelUtils.generateCodeOfType;
 
 /**
  * Represents type define information extended to support java code generation.
  */
-public class YangJavaTypeDef extends YangTypeDef
-        implements JavaCodeGenerator, HasJavaFileInfo, HasJavaImportData, HasTempJavaCodeFragmentFiles {
+public class YangJavaTypeDef extends YangTypeDef implements JavaCodeGeneratorInfo, JavaCodeGenerator {
 
     /**
      * Contains the information of the java file being generated.
@@ -106,7 +97,7 @@
      * Sets the data of java imports to be included in generated file.
      *
      * @param javaImportData data of java imports to be included in generated
-     *            file
+     *                       file
      */
     @Override
     public void setJavaImportData(JavaImportData javaImportData) {
@@ -142,23 +133,7 @@
      */
     @Override
     public void generateCodeEntry(YangPluginConfig yangPlugin) throws IOException {
-
-        getJavaFileInfo().setJavaName(getCaptialCase(getCamelCase(getName(), yangPlugin.getConflictResolver())));
-        getJavaFileInfo().setPackage(getCurNodePackage(this));
-
-        getJavaFileInfo().setPackageFilePath(
-                getPackageDirPathFromJavaJPackage(getJavaFileInfo().getPackage()));
-        getJavaFileInfo().setBaseCodeGenPath(yangPlugin.getCodeGenDir());
-        String absloutePath = getAbsolutePackagePath(
-                getJavaFileInfo().getBaseCodeGenPath(),
-                getJavaFileInfo().getPackageFilePath());
-
-        setTempJavaCodeFragmentFiles(new TempJavaCodeFragmentFiles(
-                getJavaFileInfo().getGeneratedFileTypes(), absloutePath,
-                getJavaFileInfo().getJavaName()));
-
-        getTempJavaCodeFragmentFiles().addTypeDefAttributeToTempFiles(this);
-
+        generateCodeOfType(this, yangPlugin, false);
     }
 
     /**
diff --git a/src/main/java/org/onosproject/yangutils/translator/tojava/javamodel/YangJavaUnion.java b/src/main/java/org/onosproject/yangutils/translator/tojava/javamodel/YangJavaUnion.java
new file mode 100644
index 0000000..8280184
--- /dev/null
+++ b/src/main/java/org/onosproject/yangutils/translator/tojava/javamodel/YangJavaUnion.java
@@ -0,0 +1,150 @@
+/*
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.yangutils.translator.tojava.javamodel;
+
+import java.io.IOException;
+import org.onosproject.yangutils.datamodel.YangUnion;
+import org.onosproject.yangutils.translator.tojava.JavaCodeGenerator;
+import org.onosproject.yangutils.translator.tojava.JavaFileInfo;
+import org.onosproject.yangutils.translator.tojava.JavaImportData;
+import org.onosproject.yangutils.translator.tojava.TempJavaCodeFragmentFiles;
+import org.onosproject.yangutils.translator.tojava.utils.YangPluginConfig;
+
+import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.GENERATE_UNION_CLASS;
+import static org.onosproject.yangutils.translator.tojava.utils.YangJavaModelUtils.generateCodeOfType;
+
+/**
+ * Represents union information extended to support java code generation.
+ */
+public class YangJavaUnion extends YangUnion implements JavaCodeGeneratorInfo, JavaCodeGenerator {
+
+    /**
+     * Contains the information of the java file being generated.
+     */
+    private JavaFileInfo javaFileInfo;
+
+    /**
+     * Contains information of the imports to be inserted in the java file
+     * generated.
+     */
+    private JavaImportData javaImportData;
+
+    /**
+     * File handle to maintain temporary java code fragments as per the code
+     * snippet types.
+     */
+    private TempJavaCodeFragmentFiles tempFileHandle;
+
+    /**
+     * Creates an instance of YANG java union.
+     */
+    public YangJavaUnion() {
+        super();
+        setJavaFileInfo(new JavaFileInfo());
+        setJavaImportData(new JavaImportData());
+        getJavaFileInfo().setGeneratedFileTypes(GENERATE_UNION_CLASS);
+    }
+
+    /**
+     * Returns the generated java file information.
+     *
+     * @return generated java file information
+     */
+    @Override
+    public JavaFileInfo getJavaFileInfo() {
+        if (javaFileInfo == null) {
+            throw new RuntimeException("Missing java info in java datamodel node");
+        }
+        return javaFileInfo;
+    }
+
+    /**
+     * Sets the java file info object.
+     *
+     * @param javaInfo java file info object
+     */
+    @Override
+    public void setJavaFileInfo(JavaFileInfo javaInfo) {
+        javaFileInfo = javaInfo;
+    }
+
+    /**
+     * Returns the data of java imports to be included in generated file.
+     *
+     * @return data of java imports to be included in generated file
+     */
+    @Override
+    public JavaImportData getJavaImportData() {
+        return javaImportData;
+    }
+
+    /**
+     * Sets the data of java imports to be included in generated file.
+     *
+     * @param javaImportData data of java imports to be included in generated
+     *                       file
+     */
+    @Override
+    public void setJavaImportData(JavaImportData javaImportData) {
+        this.javaImportData = javaImportData;
+    }
+
+    /**
+     * Returns the temporary file handle.
+     *
+     * @return temporary file handle
+     */
+    @Override
+    public TempJavaCodeFragmentFiles getTempJavaCodeFragmentFiles() {
+        if (tempFileHandle == null) {
+            throw new RuntimeException("Missing temp file hand for current node "
+                    + getJavaFileInfo().getJavaName());
+        }
+        return tempFileHandle;
+    }
+
+    /**
+     * Sets temporary file handle.
+     *
+     * @param fileHandle temporary file handle
+     */
+    @Override
+    public void setTempJavaCodeFragmentFiles(TempJavaCodeFragmentFiles fileHandle) {
+        tempFileHandle = fileHandle;
+    }
+
+    /**
+     * Prepare the information for java code generation corresponding to YANG
+     * union info.
+     *
+     * @param yangPlugin YANG plugin config
+     * @throws IOException IO operations fails
+     */
+    @Override
+    public void generateCodeEntry(YangPluginConfig yangPlugin) throws IOException {
+        generateCodeOfType(this, yangPlugin, false);
+    }
+
+    /**
+     * Creates a java file using the YANG union info.
+     *
+     * @throws IOException IO operations fails
+     */
+    @Override
+    public void generateCodeExit() throws IOException {
+        getTempJavaCodeFragmentFiles().generateJavaFile(GENERATE_UNION_CLASS, this);
+    }
+}
diff --git a/src/main/java/org/onosproject/yangutils/translator/tojava/utils/AttributesJavaDataType.java b/src/main/java/org/onosproject/yangutils/translator/tojava/utils/AttributesJavaDataType.java
index 077e39f..64fdf04 100644
--- a/src/main/java/org/onosproject/yangutils/translator/tojava/utils/AttributesJavaDataType.java
+++ b/src/main/java/org/onosproject/yangutils/translator/tojava/utils/AttributesJavaDataType.java
@@ -21,10 +21,12 @@
 import org.onosproject.yangutils.datamodel.YangNode;
 import org.onosproject.yangutils.datamodel.YangType;
 import org.onosproject.yangutils.datamodel.YangTypeDef;
+import org.onosproject.yangutils.datamodel.YangUnion;
 import org.onosproject.yangutils.translator.exception.TranslatorException;
 import org.onosproject.yangutils.translator.tojava.HasJavaFileInfo;
 import org.onosproject.yangutils.translator.tojava.JavaFileInfo;
 import org.onosproject.yangutils.translator.tojava.javamodel.YangJavaTypeDef;
+import org.onosproject.yangutils.translator.tojava.javamodel.YangJavaUnion;
 
 import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getCamelCase;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getCaptialCase;
@@ -33,15 +35,23 @@
 import static org.onosproject.yangutils.utils.UtilConstants.BOOLEAN_WRAPPER;
 import static org.onosproject.yangutils.utils.UtilConstants.BYTE;
 import static org.onosproject.yangutils.utils.UtilConstants.BYTE_WRAPPER;
+import static org.onosproject.yangutils.utils.UtilConstants.EMPTY_STRING;
 import static org.onosproject.yangutils.utils.UtilConstants.INT;
 import static org.onosproject.yangutils.utils.UtilConstants.INTEGER_WRAPPER;
 import static org.onosproject.yangutils.utils.UtilConstants.JAVA_LANG;
 import static org.onosproject.yangutils.utils.UtilConstants.JAVA_MATH;
 import static org.onosproject.yangutils.utils.UtilConstants.LONG;
 import static org.onosproject.yangutils.utils.UtilConstants.LONG_WRAPPER;
+import static org.onosproject.yangutils.utils.UtilConstants.NEW;
+import static org.onosproject.yangutils.utils.UtilConstants.OF;
+import static org.onosproject.yangutils.utils.UtilConstants.PARSE_BYTE;
+import static org.onosproject.yangutils.utils.UtilConstants.PARSE_INT;
+import static org.onosproject.yangutils.utils.UtilConstants.PARSE_LONG;
+import static org.onosproject.yangutils.utils.UtilConstants.PARSE_SHORT;
 import static org.onosproject.yangutils.utils.UtilConstants.PERIOD;
 import static org.onosproject.yangutils.utils.UtilConstants.SHORT;
 import static org.onosproject.yangutils.utils.UtilConstants.SHORT_WRAPPER;
+import static org.onosproject.yangutils.utils.UtilConstants.SPACE;
 import static org.onosproject.yangutils.utils.UtilConstants.STRING_DATA_TYPE;
 
 /**
@@ -94,9 +104,56 @@
     }
 
     /**
+     * Returns from string method parsed string.
+     *
+     * @param targetDataType target data type
+     * @param yangType       YANG type
+     * @return parsed string
+     */
+    public static String getParseFromStringMethod(String targetDataType, YangType<?> yangType) {
+
+        YangDataTypes type = yangType.getDataType();
+
+        switch (type) {
+            case INT8:
+                return BYTE_WRAPPER + PERIOD + PARSE_BYTE;
+            case INT16:
+                return SHORT_WRAPPER + PERIOD + PARSE_SHORT;
+            case INT32:
+                return INTEGER_WRAPPER + PERIOD + PARSE_INT;
+            case INT64:
+                return LONG_WRAPPER + PERIOD + PARSE_LONG;
+            case UINT8:
+                return SHORT_WRAPPER + PERIOD + PARSE_SHORT;
+            case UINT16:
+                return INTEGER_WRAPPER + PERIOD + PARSE_INT;
+            case UINT32:
+                return LONG_WRAPPER + PERIOD + PARSE_LONG;
+            case UINT64:
+                return NEW + SPACE + BIG_INTEGER;
+            case DECIMAL64:
+                //TODO: DECIMAL64.
+            case STRING:
+                return EMPTY_STRING;
+            case BOOLEAN:
+                return BOOLEAN_DATA_TYPE;
+            case ENUMERATION:
+                //TODO:ENUMERATION.
+            case BITS:
+                //TODO:BITS
+            case BINARY:
+                //TODO:BINARY
+            case DERIVED:
+                return targetDataType + PERIOD + OF;
+            default:
+                throw new TranslatorException("given data type is not supported.");
+        }
+    }
+
+    /**
      * Returns java import class.
      *
-     * @param yangType YANG type
+     * @param yangType   YANG type
      * @param isListAttr if the attribute need to be a list
      * @return java import class
      */
@@ -141,13 +198,14 @@
                 case EMPTY:
                     return BOOLEAN_WRAPPER;
                 case UNION:
-                    //TODO:UNION
+                    return getCaptialCase(getCamelCase(((YangJavaUnion) yangType.getDataTypeExtendedInfo()).getName(),
+                            null));
                 case INSTANCE_IDENTIFIER:
                     //TODO:INSTANCE_IDENTIFIER
                 case DERIVED:
                     return getCaptialCase(getCamelCase(yangType.getDataTypeName(), null));
                 default:
-                    throw new TranslatorException("given data type is not supported.");
+                    return null;
             }
         } else {
             switch (type) {
@@ -170,7 +228,8 @@
                 case EMPTY:
                     //TODO:EMPTY
                 case UNION:
-                    //TODO:UNION
+                    return getCaptialCase(getCamelCase(((YangJavaUnion) yangType.getDataTypeExtendedInfo()).getName(),
+                            null));
                 case INSTANCE_IDENTIFIER:
                     //TODO:INSTANCE_IDENTIFIER
                 case DERIVED:
@@ -184,9 +243,9 @@
     /**
      * Returns java import package.
      *
-     * @param yangType YANG type
+     * @param yangType   YANG type
      * @param isListAttr if the attribute is of list type
-     * @param classInfo java import class info
+     * @param classInfo  java import class info
      * @return java import package
      */
     public static String getJavaImportPackage(YangType<?> yangType, boolean isListAttr, String classInfo) {
@@ -222,13 +281,13 @@
                 case EMPTY:
                     //TODO:EMPTY
                 case UNION:
-                    //TODO:UNION
+                    return getUnionPackage(yangType);
                 case INSTANCE_IDENTIFIER:
                     //TODO:INSTANCE_IDENTIFIER
                 case DERIVED:
                     return getTypDefsPackage(yangType);
                 default:
-                    throw new TranslatorException("given data type is not supported.");
+                    return null;
             }
         } else {
             switch (type) {
@@ -251,7 +310,7 @@
                 case EMPTY:
                     //TODO:EMPTY
                 case UNION:
-                    //TODO:UNION
+                    return getUnionPackage(yangType);
                 case INSTANCE_IDENTIFIER:
                     //TODO:INSTANCE_IDENTIFIER
                 case DERIVED:
@@ -286,6 +345,25 @@
     }
 
     /**
+     * Returns java package for union node.
+     *
+     * @param type YANG type
+     * @return java package for union node
+     */
+    private static String getUnionPackage(YangType<?> type) {
+
+        if (!(type.getDataTypeExtendedInfo() instanceof YangUnion)) {
+            throw new TranslatorException("type should have been union.");
+        }
+
+        YangJavaUnion union = (YangJavaUnion) type.getDataTypeExtendedInfo();
+        if (union.getJavaFileInfo().getPackage() == null) {
+            return getPackageFromParent(union.getParent());
+        }
+        return union.getJavaFileInfo().getPackage();
+    }
+
+    /**
      * Returns package from parent node.
      *
      * @param parent parent YANG node
@@ -293,7 +371,7 @@
      */
     private static String getPackageFromParent(YangNode parent) {
         if (!(parent instanceof HasJavaFileInfo)) {
-            throw new TranslatorException("Invalid child node is being processed.");
+            throw new TranslatorException("invalid child node is being processed.");
         }
         JavaFileInfo parentInfo = ((HasJavaFileInfo) parent).getJavaFileInfo();
         return parentInfo.getPackage() + PERIOD + parentInfo.getJavaName().toLowerCase();
diff --git a/src/main/java/org/onosproject/yangutils/translator/tojava/utils/ClassDefinitionGenerator.java b/src/main/java/org/onosproject/yangutils/translator/tojava/utils/ClassDefinitionGenerator.java
index f3adba0..529a93d 100644
--- a/src/main/java/org/onosproject/yangutils/translator/tojava/utils/ClassDefinitionGenerator.java
+++ b/src/main/java/org/onosproject/yangutils/translator/tojava/utils/ClassDefinitionGenerator.java
@@ -19,6 +19,7 @@
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.BUILDER_CLASS_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.BUILDER_INTERFACE_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.GENERATE_TYPEDEF_CLASS;
+import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.GENERATE_UNION_CLASS;
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.IMPL_CLASS_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.INTERFACE_MASK;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaFileGenerator.getExtendsList;
@@ -54,7 +55,7 @@
      * / interface definition start.
      *
      * @param genFileTypes generated file type
-     * @param yangName class name
+     * @param yangName     class name
      * @return class definition
      */
     public static String generateClassDefinition(int genFileTypes, String yangName) {
@@ -64,20 +65,17 @@
          * class / interface definition start.
          */
         if ((genFileTypes & INTERFACE_MASK) != 0) {
-
             return getInterfaceDefinition(yangName);
         } else if ((genFileTypes & BUILDER_CLASS_MASK) != 0) {
-
             return getBuilderClassDefinition(yangName);
         } else if ((genFileTypes & IMPL_CLASS_MASK) != 0) {
-
             return getImplClassDefinition(yangName);
         } else if ((genFileTypes & BUILDER_INTERFACE_MASK) != 0) {
-
             return getBuilderInterfaceDefinition(yangName);
         } else if ((genFileTypes & GENERATE_TYPEDEF_CLASS) != 0) {
-
-            return getTypeDefClassDefinition(yangName);
+            return getTypeClassDefinition(yangName);
+        } else if ((genFileTypes & GENERATE_UNION_CLASS) != 0) {
+            return getTypeClassDefinition(yangName);
         }
         return null;
     }
@@ -105,7 +103,7 @@
      * Returns builder interface file class definition.
      *
      * @param yangName java class name, corresponding to which the builder class
-     *            is being generated
+     *                 is being generated
      * @return definition
      */
     private static String getBuilderInterfaceDefinition(String yangName) {
@@ -135,12 +133,12 @@
     }
 
     /**
-     * Returns typeDef file class definition.
+     * Returns type file class definition.
      *
      * @param yangName file name
      * @return definition
      */
-    private static String getTypeDefClassDefinition(String yangName) {
+    private static String getTypeClassDefinition(String yangName) {
         return PUBLIC + SPACE + FINAL + SPACE + CLASS + SPACE + yangName + SPACE + OPEN_CURLY_BRACKET + NEW_LINE;
     }
 }
diff --git a/src/main/java/org/onosproject/yangutils/translator/tojava/utils/JavaFileGenerator.java b/src/main/java/org/onosproject/yangutils/translator/tojava/utils/JavaFileGenerator.java
index 08b3072..6fc37a5 100644
--- a/src/main/java/org/onosproject/yangutils/translator/tojava/utils/JavaFileGenerator.java
+++ b/src/main/java/org/onosproject/yangutils/translator/tojava/utils/JavaFileGenerator.java
@@ -20,7 +20,6 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
-
 import org.onosproject.yangutils.datamodel.YangNode;
 import org.onosproject.yangutils.translator.tojava.HasJavaFileInfo;
 import org.onosproject.yangutils.translator.tojava.HasTempJavaCodeFragmentFiles;
@@ -29,17 +28,21 @@
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.BUILDER_CLASS_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.BUILDER_INTERFACE_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.GENERATE_TYPEDEF_CLASS;
+import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.GENERATE_UNION_CLASS;
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.IMPL_CLASS_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.INTERFACE_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.ATTRIBUTES_MASK;
+import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.CONSTRUCTOR_FOR_TYPE_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.CONSTRUCTOR_IMPL_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.EQUALS_IMPL_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.GETTER_FOR_CLASS_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.GETTER_FOR_INTERFACE_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.HASH_CODE_IMPL_MASK;
+import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.OF_STRING_IMPL_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.SETTER_FOR_CLASS_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.SETTER_FOR_INTERFACE_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.TO_STRING_IMPL_MASK;
+import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.UNION_FROM_STRING_IMPL_MASK;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaCodeSnippetGen.getAugmentedInfoAttribute;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaFileGeneratorUtils.getDataFromTempFileHandle;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaFileGeneratorUtils.initiateJavaFileGeneration;
@@ -49,8 +52,11 @@
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getConstructorStart;
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getEqualsMethodClose;
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getEqualsMethodOpen;
+import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getFromStringMethodClose;
+import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getFromStringMethodSignature;
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getHashCodeMethodClose;
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getHashCodeMethodOpen;
+import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getOmitNullValueString;
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getRemoveAugmentationImpl;
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getToStringMethodClose;
 import static org.onosproject.yangutils.translator.tojava.utils.MethodsGenerator.getToStringMethodOpen;
@@ -82,8 +88,8 @@
     private static List<String> extendsList = new ArrayList<>();
 
     /**
-    * Creates an instance of java file generator.
-    */
+     * Creates an instance of java file generator.
+     */
     private JavaFileGenerator() {
     }
 
@@ -126,10 +132,10 @@
     /**
      * Returns generated interface file for current node.
      *
-     * @param file file
-     * @param imports imports for the file
-     * @param curNode current YANG node
-     * @param isAttrPresent  if any attribute is present or not
+     * @param file          file
+     * @param imports       imports for the file
+     * @param curNode       current YANG node
+     * @param isAttrPresent if any attribute is present or not
      * @return interface file
      * @throws IOException when fails to write in file
      */
@@ -163,9 +169,9 @@
     /**
      * Return generated builder interface file for current node.
      *
-     * @param file file
-     * @param curNode current YANG node
-     * @param isAttrPresent  if any attribute is present or not
+     * @param file          file
+     * @param curNode       current YANG node
+     * @param isAttrPresent if any attribute is present or not
      * @return builder interface file
      * @throws IOException when fails to write in file
      */
@@ -215,15 +221,15 @@
     /**
      * Returns generated builder class file for current node.
      *
-     * @param file file
-     * @param imports imports for the file
-     * @param curNode current YANG node
-     * @param isAttrPresent  if any attribute is present or not
+     * @param file          file
+     * @param imports       imports for the file
+     * @param curNode       current YANG node
+     * @param isAttrPresent if any attribute is present or not
      * @return builder class file
      * @throws IOException when fails to write in file
      */
     public static File generateBuilderClassFile(File file, List<String> imports, YangNode curNode,
-            boolean isAttrPresent) throws IOException {
+                                                boolean isAttrPresent) throws IOException {
 
         JavaFileInfo javaFileInfo = ((HasJavaFileInfo) curNode).getJavaFileInfo();
 
@@ -281,8 +287,8 @@
     /**
      * Returns generated impl class file for current node.
      *
-     * @param file file
-     * @param curNode current YANG node
+     * @param file          file
+     * @param curNode       current YANG node
      * @param isAttrPresent if any attribute is present or not
      * @return impl class file
      * @throws IOException when fails to write in file
@@ -378,14 +384,14 @@
     }
 
     /**
-     * Generates class file for type def.
+     * Generate class file for type def.
      *
-     * @param file generated file
+     * @param file    generated file
      * @param curNode current YANG node
      * @param imports imports for file
      * @return type def class file
      * @throws IOException when fails to generate class file
-    */
+     */
     public static File generateTypeDefClassFile(File file, YangNode curNode, List<String> imports) throws IOException {
 
         JavaFileInfo javaFileInfo = ((HasJavaFileInfo) curNode).getJavaFileInfo();
@@ -414,19 +420,19 @@
         methods.add(((HasTempJavaCodeFragmentFiles) curNode).getTempJavaCodeFragmentFiles()
                 .addDefaultConstructor(PRIVATE, EMPTY_STRING));
 
-        /**
-         * Constructor.
-         */
-        methods.add(((HasTempJavaCodeFragmentFiles) curNode).getTempJavaCodeFragmentFiles()
-                .addTypeDefConstructor());
-
-        /**
-         * Of method.
-         */
-        methods.add(((HasTempJavaCodeFragmentFiles) curNode).getTempJavaCodeFragmentFiles().addOfMethod());
         try {
 
             /**
+             * Type constructor.
+             */
+            methods.add(getDataFromTempFileHandle(CONSTRUCTOR_FOR_TYPE_MASK, curNode));
+
+            /**
+             * Of method.
+             */
+            methods.add(getDataFromTempFileHandle(OF_STRING_IMPL_MASK, curNode));
+
+            /**
              * Getter method.
              */
             methods.add(getDataFromTempFileHandle(GETTER_FOR_CLASS_MASK, curNode));
@@ -461,4 +467,96 @@
 
         return file;
     }
+
+    /**
+     * Generate class file for union type.
+     *
+     * @param file    generated file
+     * @param curNode current YANG node
+     * @param imports imports for file
+     * @return type def class file
+     * @throws IOException when fails to generate class file
+     */
+    public static File generateUnionClassFile(File file, YangNode curNode, List<String> imports) throws IOException {
+
+        JavaFileInfo javaFileInfo = ((HasJavaFileInfo) curNode).getJavaFileInfo();
+
+        String className = getCaptialCase(javaFileInfo.getJavaName());
+        String path = javaFileInfo.getBaseCodeGenPath() + javaFileInfo.getPackageFilePath();
+
+        initiateJavaFileGeneration(file, className, GENERATE_UNION_CLASS, imports, path);
+
+        List<String> methods = new ArrayList<>();
+
+        /**
+         * Add attribute strings.
+         */
+        try {
+            insertDataIntoJavaFile(file,
+                    NEW_LINE + FOUR_SPACE_INDENTATION + getDataFromTempFileHandle(ATTRIBUTES_MASK, curNode));
+        } catch (IOException e) {
+            throw new IOException("No data found in temporary java code fragment files for " + className
+                    + " while union class file generation");
+        }
+
+        /**
+         * Default constructor.
+         */
+        methods.add(((HasTempJavaCodeFragmentFiles) curNode).getTempJavaCodeFragmentFiles()
+                .addDefaultConstructor(PRIVATE, EMPTY_STRING));
+
+        try {
+
+            /**
+             * Type constructor.
+             */
+            methods.add(getDataFromTempFileHandle(CONSTRUCTOR_FOR_TYPE_MASK, curNode));
+
+            /**
+             * Of string method.
+             */
+            methods.add(getDataFromTempFileHandle(OF_STRING_IMPL_MASK, curNode));
+
+            /**
+             * Getter method.
+             */
+            methods.add(getDataFromTempFileHandle(GETTER_FOR_CLASS_MASK, curNode));
+
+            /**
+             * Hash code method.
+             */
+            methods.add(getHashCodeMethodClose(getHashCodeMethodOpen() + partString(
+                    getDataFromTempFileHandle(HASH_CODE_IMPL_MASK, curNode).replace(NEW_LINE, EMPTY_STRING))));
+
+            /**
+             * Equals method.
+             */
+            methods.add(getEqualsMethodClose(getEqualsMethodOpen(className + EMPTY_STRING)
+                    + getDataFromTempFileHandle(EQUALS_IMPL_MASK, curNode)));
+
+            /**
+             * To string method.
+             */
+            methods.add(getToStringMethodOpen() + getOmitNullValueString() +
+                    getDataFromTempFileHandle(TO_STRING_IMPL_MASK, curNode) + getToStringMethodClose());
+
+            /**
+             * From string method.
+             */
+            methods.add(getFromStringMethodSignature(className)
+                    + getDataFromTempFileHandle(UNION_FROM_STRING_IMPL_MASK, curNode)
+                    + getFromStringMethodClose());
+
+        } catch (IOException e) {
+            throw new IOException("No data found in temporary java code fragment files for " + className
+                    + " while union class file generation");
+        }
+
+        for (String method : methods) {
+            insertDataIntoJavaFile(file, method);
+        }
+        insertDataIntoJavaFile(file, CLOSE_CURLY_BRACKET + NEW_LINE);
+
+        return file;
+    }
 }
diff --git a/src/main/java/org/onosproject/yangutils/translator/tojava/utils/JavaFileGeneratorUtils.java b/src/main/java/org/onosproject/yangutils/translator/tojava/utils/JavaFileGeneratorUtils.java
index 4228a2e..6aa3ead 100644
--- a/src/main/java/org/onosproject/yangutils/translator/tojava/utils/JavaFileGeneratorUtils.java
+++ b/src/main/java/org/onosproject/yangutils/translator/tojava/utils/JavaFileGeneratorUtils.java
@@ -19,7 +19,6 @@
 import java.io.File;
 import java.io.IOException;
 import java.util.List;
-
 import org.onosproject.yangutils.datamodel.YangNode;
 import org.onosproject.yangutils.translator.tojava.HasTempJavaCodeFragmentFiles;
 import org.onosproject.yangutils.translator.tojava.JavaFileInfo;
@@ -30,17 +29,21 @@
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.BUILDER_CLASS_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.BUILDER_INTERFACE_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.GENERATE_TYPEDEF_CLASS;
+import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.GENERATE_UNION_CLASS;
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.IMPL_CLASS_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedJavaFileType.INTERFACE_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.ATTRIBUTES_MASK;
+import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.CONSTRUCTOR_FOR_TYPE_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.CONSTRUCTOR_IMPL_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.EQUALS_IMPL_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.GETTER_FOR_CLASS_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.GETTER_FOR_INTERFACE_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.HASH_CODE_IMPL_MASK;
+import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.OF_STRING_IMPL_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.SETTER_FOR_CLASS_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.SETTER_FOR_INTERFACE_MASK;
 import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.TO_STRING_IMPL_MASK;
+import static org.onosproject.yangutils.translator.tojava.GeneratedTempFileType.UNION_FROM_STRING_IMPL_MASK;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaCodeSnippetGen.getJavaClassDefStart;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getJavaPackageFromPackagePath;
 import static org.onosproject.yangutils.utils.UtilConstants.NEW_LINE;
@@ -49,11 +52,11 @@
 import static org.onosproject.yangutils.utils.UtilConstants.SEMI_COLAN;
 import static org.onosproject.yangutils.utils.UtilConstants.SLASH;
 import static org.onosproject.yangutils.utils.UtilConstants.SPACE;
-import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.getJavaDoc;
 import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.JavaDocType.BUILDER_CLASS;
 import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.JavaDocType.BUILDER_INTERFACE;
 import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.JavaDocType.IMPL_CLASS;
 import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.JavaDocType.INTERFACE;
+import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.getJavaDoc;
 import static org.onosproject.yangutils.utils.io.impl.YangIoUtils.insertDataIntoJavaFile;
 
 /**
@@ -70,10 +73,10 @@
     /**
      * Returns a file object for generated file.
      *
-     * @param fileName file name
-     * @param filePath file package path
+     * @param fileName  file name
+     * @param filePath  file package path
      * @param extension file extension
-     * @param handle cached file handle
+     * @param handle    cached file handle
      * @return file object
      */
     public static File getFileObject(String filePath, String fileName, String extension, JavaFileInfo handle) {
@@ -85,7 +88,7 @@
      * Returns data stored in temporary files.
      *
      * @param generatedTempFiles temporary file types
-     * @param curNode current YANG node
+     * @param curNode            current YANG node
      * @return data stored in temporary files
      * @throws IOException when failed to get the data from temporary file handle
      */
@@ -121,6 +124,16 @@
         } else if ((generatedTempFiles & TO_STRING_IMPL_MASK) != 0) {
             return tempJavaCodeFragmentFiles
                     .getTemporaryDataFromFileHandle(tempJavaCodeFragmentFiles.getToStringImplTempFileHandle());
+        } else if ((generatedTempFiles & CONSTRUCTOR_FOR_TYPE_MASK) != 0) {
+            return tempJavaCodeFragmentFiles
+                    .getTemporaryDataFromFileHandle(tempJavaCodeFragmentFiles
+                            .getConstructorForTypeTempFileHandle());
+        } else if ((generatedTempFiles & OF_STRING_IMPL_MASK) != 0) {
+            return tempJavaCodeFragmentFiles
+                    .getTemporaryDataFromFileHandle(tempJavaCodeFragmentFiles.getOfStringImplTempFileHandle());
+        } else if ((generatedTempFiles & UNION_FROM_STRING_IMPL_MASK) != 0) {
+            return tempJavaCodeFragmentFiles
+                    .getTemporaryDataFromFileHandle(tempJavaCodeFragmentFiles.getUnionFromStringImplTempFileHandle());
         }
         return null;
     }
@@ -128,15 +141,15 @@
     /**
      * Initiates generation of file based on generated file type.
      *
-     * @param file generated file
+     * @param file      generated file
      * @param className generated file class name
-     * @param type generated file type
-     * @param imports imports for the file
-     * @param pkg generated file package
+     * @param type      generated file type
+     * @param imports   imports for the file
+     * @param pkg       generated file package
      * @throws IOException when fails to generate a file
      */
     public static void initiateJavaFileGeneration(File file, String className, int type, List<String> imports,
-            String pkg) throws IOException {
+                                                  String pkg) throws IOException {
 
         try {
             file.createNewFile();
@@ -149,42 +162,41 @@
     /**
      * Appends all the contents into a generated java file.
      *
-     * @param file generated file
-     * @param fileName generated file name
-     * @param type generated file type
-     * @param pkg generated file package
+     * @param file        generated file
+     * @param fileName    generated file name
+     * @param type        generated file type
+     * @param pkg         generated file package
      * @param importsList list of java imports.
      * @throws IOException when fails to append contents
      */
     private static void appendContents(File file, String fileName, int type, List<String> importsList,
-            String pkg) throws IOException {
+                                       String pkg) throws IOException {
 
         String pkgString = parsePackageString(pkg, importsList);
 
         if ((type & IMPL_CLASS_MASK) != 0) {
-
             write(file, fileName, type, IMPL_CLASS);
         } else if ((type & BUILDER_INTERFACE_MASK) != 0) {
-
             write(file, fileName, type, BUILDER_INTERFACE);
         } else if ((type & GENERATE_TYPEDEF_CLASS) != 0) {
             appendHeaderContents(file, pkgString, importsList);
             write(file, fileName, type, IMPL_CLASS);
         } else if ((type & INTERFACE_MASK) != 0) {
-
             appendHeaderContents(file, pkgString, importsList);
             write(file, fileName, type, INTERFACE);
         } else if ((type & BUILDER_CLASS_MASK) != 0) {
-
             appendHeaderContents(file, pkgString, importsList);
             write(file, fileName, type, BUILDER_CLASS);
+        } else if ((type & GENERATE_UNION_CLASS) != 0) {
+            appendHeaderContents(file, pkgString, importsList);
+            write(file, fileName, type, IMPL_CLASS);
         }
     }
 
     /**
      * Removes base directory path from package and generates package string for file.
      *
-     * @param javaPkg generated java package
+     * @param javaPkg     generated java package
      * @param importsList list of imports
      * @return package string
      */
@@ -208,10 +220,11 @@
     /**
      * Appends other contents to interface, builder and typedef classes.
      * for example : ONOS copyright, imports and package.
-     * @param file generated file
-     * @param pkg generated package
+     *
+     * @param file        generated file
+     * @param pkg         generated package
      * @param importsList list of imports
-     * @throws IOException when fails to append contents.
+     * @throws IOException when fails to append contents
      */
     private static void appendHeaderContents(File file, String pkg, List<String> importsList) throws IOException {
 
@@ -234,15 +247,14 @@
     /**
      * Writes data to the specific generated file.
      *
-     * @param file generated file
-     * @param fileName file name
-     * @param genType generated file type
+     * @param file        generated file
+     * @param fileName    file name
+     * @param genType     generated file type
      * @param javaDocType java doc type
      * @throws IOException when fails to write into a file
      */
     private static void write(File file, String fileName, int genType, JavaDocType javaDocType)
             throws IOException {
-
         insertDataIntoJavaFile(file, getJavaDoc(javaDocType, fileName, false));
         insertDataIntoJavaFile(file, getJavaClassDefStart(genType, fileName));
     }
diff --git a/src/main/java/org/onosproject/yangutils/translator/tojava/utils/MethodsGenerator.java b/src/main/java/org/onosproject/yangutils/translator/tojava/utils/MethodsGenerator.java
index 154090d..ec1296f 100644
--- a/src/main/java/org/onosproject/yangutils/translator/tojava/utils/MethodsGenerator.java
+++ b/src/main/java/org/onosproject/yangutils/translator/tojava/utils/MethodsGenerator.java
@@ -18,6 +18,7 @@
 
 import org.onosproject.yangutils.translator.tojava.JavaAttributeInfo;
 
+import static org.onosproject.yangutils.translator.tojava.utils.AttributesJavaDataType.getParseFromStringMethod;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getCamelCase;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getCaptialCase;
 import static org.onosproject.yangutils.translator.tojava.utils.JavaIdentifierSyntax.getSmallCase;
@@ -28,7 +29,9 @@
 import static org.onosproject.yangutils.utils.UtilConstants.BOOLEAN_DATA_TYPE;
 import static org.onosproject.yangutils.utils.UtilConstants.BUILD;
 import static org.onosproject.yangutils.utils.UtilConstants.BUILDER;
+import static org.onosproject.yangutils.utils.UtilConstants.CATCH;
 import static org.onosproject.yangutils.utils.UtilConstants.CHECK_NOT_NULL_STRING;
+import static org.onosproject.yangutils.utils.UtilConstants.CLEAR;
 import static org.onosproject.yangutils.utils.UtilConstants.CLOSE_CURLY_BRACKET;
 import static org.onosproject.yangutils.utils.UtilConstants.CLOSE_PARENTHESIS;
 import static org.onosproject.yangutils.utils.UtilConstants.COMMA;
@@ -38,8 +41,12 @@
 import static org.onosproject.yangutils.utils.UtilConstants.EMPTY_STRING;
 import static org.onosproject.yangutils.utils.UtilConstants.EQUAL;
 import static org.onosproject.yangutils.utils.UtilConstants.EQUALS_STRING;
+import static org.onosproject.yangutils.utils.UtilConstants.EXCEPTION;
+import static org.onosproject.yangutils.utils.UtilConstants.EXCEPTION_VAR;
 import static org.onosproject.yangutils.utils.UtilConstants.FALSE;
 import static org.onosproject.yangutils.utils.UtilConstants.FOUR_SPACE_INDENTATION;
+import static org.onosproject.yangutils.utils.UtilConstants.FROM_STRING_METHOD_NAME;
+import static org.onosproject.yangutils.utils.UtilConstants.FROM_STRING_PARAM_NAME;
 import static org.onosproject.yangutils.utils.UtilConstants.GET_METHOD_PREFIX;
 import static org.onosproject.yangutils.utils.UtilConstants.GOOGLE_MORE_OBJECT_METHOD_STRING;
 import static org.onosproject.yangutils.utils.UtilConstants.HASH;
@@ -51,10 +58,12 @@
 import static org.onosproject.yangutils.utils.UtilConstants.LIST;
 import static org.onosproject.yangutils.utils.UtilConstants.NEW;
 import static org.onosproject.yangutils.utils.UtilConstants.NEW_LINE;
+import static org.onosproject.yangutils.utils.UtilConstants.NULL;
 import static org.onosproject.yangutils.utils.UtilConstants.OBJ;
 import static org.onosproject.yangutils.utils.UtilConstants.OBJECT;
 import static org.onosproject.yangutils.utils.UtilConstants.OBJECT_STRING;
 import static org.onosproject.yangutils.utils.UtilConstants.OF;
+import static org.onosproject.yangutils.utils.UtilConstants.OMIT_NULL_VALUE_STRING;
 import static org.onosproject.yangutils.utils.UtilConstants.OPEN_CURLY_BRACKET;
 import static org.onosproject.yangutils.utils.UtilConstants.OPEN_PARENTHESIS;
 import static org.onosproject.yangutils.utils.UtilConstants.OTHER;
@@ -71,17 +80,22 @@
 import static org.onosproject.yangutils.utils.UtilConstants.STRING_DATA_TYPE;
 import static org.onosproject.yangutils.utils.UtilConstants.SUFFIX_S;
 import static org.onosproject.yangutils.utils.UtilConstants.THIS;
+import static org.onosproject.yangutils.utils.UtilConstants.TMP_VAL;
 import static org.onosproject.yangutils.utils.UtilConstants.TO;
 import static org.onosproject.yangutils.utils.UtilConstants.TRUE;
+import static org.onosproject.yangutils.utils.UtilConstants.TRY;
 import static org.onosproject.yangutils.utils.UtilConstants.TWELVE_SPACE_INDENTATION;
 import static org.onosproject.yangutils.utils.UtilConstants.VALUE;
 import static org.onosproject.yangutils.utils.UtilConstants.VOID;
-import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.getJavaDoc;
 import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.JavaDocType.BUILD_METHOD;
 import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.JavaDocType.CONSTRUCTOR;
 import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.JavaDocType.DEFAULT_CONSTRUCTOR;
 import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.JavaDocType.GETTER_METHOD;
+import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.JavaDocType.OF_METHOD;
 import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.JavaDocType.SETTER_METHOD;
+import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.JavaDocType.TYPE_CONSTRUCTOR;
+import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.JavaDocType.UNION_FROM_METHOD;
+import static org.onosproject.yangutils.utils.io.impl.JavaDocGen.getJavaDoc;
 import static org.onosproject.yangutils.utils.io.impl.YangIoUtils.trimAtLast;
 
 /**
@@ -123,7 +137,7 @@
     /**
      * Returns setter string.
      *
-     * @param attr attribute info
+     * @param attr      attribute info
      * @param className java class name
      * @return setter string
      */
@@ -149,46 +163,13 @@
     /**
      * Returns default constructor method string.
      *
-     * @param name class name
+     * @param name         class name
      * @param modifierType modifier type
      * @return default constructor string
      */
     public static String getDefaultConstructorString(String name, String modifierType) {
-        return getJavaDoc(DEFAULT_CONSTRUCTOR, name, false) + getDefaultConstructor(name, modifierType);
-    }
-
-    /**
-     * Returns default constructor method string.
-     *
-     * @param attr attribute info
-     * @param className class name
-     * @return default constructor string
-     */
-    public static String getTypeDefConstructor(JavaAttributeInfo attr, String className) {
-
-        String attrQuaifiedType = getReturnType(attr);
-        String attributeName = getSmallCase(attr.getAttributeName());
-
-        if (!attr.isListAttr()) {
-            return getTypeDefConstructorString(attrQuaifiedType, attributeName, className);
-        }
-        String listAttr = getListString() + attrQuaifiedType + DIAMOND_CLOSE_BRACKET;
-        return getTypeDefConstructorString(listAttr, attributeName, className);
-    }
-
-    /**
-     * Returns type def's constructor for attribute.
-     *
-     * @param type data type
-     * @param name attribute name
-     * @param className class name
-     * @return setter for type def's attribute
-     */
-    private static String getTypeDefConstructorString(String type, String name, String className) {
-        return FOUR_SPACE_INDENTATION + PUBLIC + SPACE + className + OPEN_PARENTHESIS + type + SPACE + VALUE
-                + CLOSE_PARENTHESIS + SPACE + OPEN_CURLY_BRACKET + NEW_LINE + EIGHT_SPACE_INDENTATION + THIS + PERIOD
-                + name + SPACE + EQUAL + SPACE + VALUE + SEMI_COLAN + NEW_LINE + FOUR_SPACE_INDENTATION
-                + CLOSE_CURLY_BRACKET;
+        return getJavaDoc(DEFAULT_CONSTRUCTOR, name, false) + getDefaultConstructor(name, modifierType)
+                + NEW_LINE;
     }
 
     /**
@@ -246,7 +227,7 @@
     /**
      * Returns the setter method strings for class file.
      *
-     * @param attr attribute info
+     * @param attr      attribute info
      * @param className name of the class
      * @return setter method for class
      */
@@ -265,8 +246,8 @@
      * Returns setter for attribute.
      *
      * @param className class name
-     * @param name attribute name
-     * @param type return type
+     * @param name      attribute name
+     * @param type      return type
      * @return setter for attribute
      */
     private static String getSetter(String className, String name, String type) {
@@ -316,9 +297,9 @@
     /**
      * Returns the getter method strings for interface file.
      *
-     * @param yangName name of the attribute
+     * @param yangName   name of the attribute
      * @param returnType return type of attribute
-     * @param isList is list attribute
+     * @param isList     is list attribute
      * @return getter method for interface
      */
     public static String getGetterForInterface(String yangName, String returnType, boolean isList) {
@@ -334,7 +315,7 @@
      * Returns getter for attribute in interface.
      *
      * @param returnType return type
-     * @param yangName attribute name
+     * @param yangName   attribute name
      * @return getter for interface
      */
     private static String getGetterInterfaceString(String returnType, String yangName) {
@@ -345,10 +326,10 @@
     /**
      * Returns the setter method strings for interface file.
      *
-     * @param attrName name of the attribute
-     * @param attrType return type of attribute
+     * @param attrName  name of the attribute
+     * @param attrType  return type of attribute
      * @param className name of the java class being generated
-     * @param isList is list attribute
+     * @param isList    is list attribute
      * @return setter method for interface
      */
     public static String getSetterForInterface(String attrName, String attrType, String className, boolean isList) {
@@ -364,8 +345,8 @@
      * Returns setter string for interface.
      *
      * @param className class name
-     * @param attrName attribute name
-     * @param attrType attribute type
+     * @param attrName  attribute name
+     * @param attrType  attribute type
      * @return setter string
      */
     private static String getSetterInterfaceString(String className, String attrName, String attrType) {
@@ -428,7 +409,7 @@
      * Returns the constructor strings for class file.
      *
      * @param yangName name of the class
-     * @param attr attribute info
+     * @param attr     attribute info
      * @return constructor for class
      */
     public static String getConstructor(String yangName, JavaAttributeInfo attr) {
@@ -459,7 +440,7 @@
     /**
      * Returns the Default constructor strings for class file.
      *
-     * @param name name of the class
+     * @param name         name of the class
      * @param modifierType modifier type for default constructor
      * @return Default constructor for class
      */
@@ -469,9 +450,9 @@
     }
 
     /**
-     * Returns to string method open strings.
+     * Returns to string method's open strings.
      *
-     * @return to string method open string
+     * @return string method's open string
      */
     public static String getToStringMethodOpen() {
         return getOverRideString() + FOUR_SPACE_INDENTATION + PUBLIC + SPACE + STRING_DATA_TYPE + SPACE + TO
@@ -480,7 +461,16 @@
     }
 
     /**
-     * Returns to string methods close string.
+     * Returns omit null value string.
+     *
+     * @return omit null value string
+     */
+    public static String getOmitNullValueString() {
+        return TWELVE_SPACE_INDENTATION + PERIOD + OMIT_NULL_VALUE_STRING + NEW_LINE;
+    }
+
+    /**
+     * Returns to string method's close string.
      *
      * @return to string method close string
      */
@@ -503,6 +493,90 @@
     }
 
     /**
+     * Returns from string method's open string.
+     *
+     * @param className name of the class
+     * @return from string method's open string
+     */
+    public static String getFromStringMethodSignature(String className) {
+        return getJavaDoc(UNION_FROM_METHOD, className, false) + FOUR_SPACE_INDENTATION + PUBLIC + SPACE
+                + className + SPACE + FROM_STRING_METHOD_NAME + OPEN_PARENTHESIS + STRING_DATA_TYPE + SPACE
+                + FROM_STRING_PARAM_NAME + CLOSE_PARENTHESIS + SPACE + OPEN_CURLY_BRACKET + NEW_LINE;
+    }
+
+    /**
+     * Return from string method's close string.
+     *
+     * @return from string method's close string
+     */
+    public static String getFromStringMethodClose() {
+        return EIGHT_SPACE_INDENTATION + RETURN + SPACE + NULL + SEMI_COLAN + NEW_LINE + FOUR_SPACE_INDENTATION +
+                CLOSE_CURLY_BRACKET + NEW_LINE;
+    }
+
+    /**
+     * Return from string method's body string.
+     *
+     * @param attr                    attribute info
+     * @param fromStringAttributeInfo attribute info for the from string
+     *                                wrapper type
+     * @return from string method's body string
+     */
+    public static String getFromStringMethod(JavaAttributeInfo attr,
+                                             JavaAttributeInfo fromStringAttributeInfo) {
+
+        return EIGHT_SPACE_INDENTATION + getTrySubString() + NEW_LINE + TWELVE_SPACE_INDENTATION
+                + getParsedSubString(attr, fromStringAttributeInfo) + SEMI_COLAN + NEW_LINE + TWELVE_SPACE_INDENTATION
+                + getReturnOfSubString() + NEW_LINE + EIGHT_SPACE_INDENTATION + getCatchSubString()
+                + NEW_LINE + EIGHT_SPACE_INDENTATION + CLOSE_CURLY_BRACKET;
+    }
+
+    /**
+     * Returns sub string with try statement for union's from string method.
+     *
+     * @return sub string with try statement for union's from string method
+     */
+    public static String getTrySubString() {
+        return TRY + SPACE + OPEN_CURLY_BRACKET;
+    }
+
+    /**
+     * Returns sub string with return statement for union's from string method.
+     *
+     * @return sub string with return statement for union's from string method
+     */
+    public static String getReturnOfSubString() {
+        return RETURN + SPACE + OF + OPEN_PARENTHESIS + TMP_VAL + CLOSE_PARENTHESIS + SEMI_COLAN;
+    }
+
+    /**
+     * Returns sub string with catch statement for union's from string method.
+     *
+     * @return sub string with catch statement for union's from string method
+     */
+    public static String getCatchSubString() {
+        return CLOSE_CURLY_BRACKET + SPACE + CATCH + SPACE + OPEN_PARENTHESIS + EXCEPTION + SPACE + EXCEPTION_VAR
+                + CLOSE_PARENTHESIS + SPACE + OPEN_CURLY_BRACKET;
+    }
+
+    /**
+     * Returns sub string with parsed statement for union's from string method.
+     *
+     * @param attr attribute info
+     * @return sub string with parsed statement for union's from string method
+     */
+    private static String getParsedSubString(JavaAttributeInfo attr,
+                                             JavaAttributeInfo fromStringAttributeInfo) {
+
+        String targetDataType = getReturnType(attr);
+        String parseFromStringMethod = getParseFromStringMethod(targetDataType,
+                fromStringAttributeInfo.getAttributeType());
+        return targetDataType + SPACE + TMP_VAL + SPACE + EQUAL + SPACE + parseFromStringMethod
+                + OPEN_PARENTHESIS + FROM_STRING_PARAM_NAME + CLOSE_PARENTHESIS;
+    }
+
+
+    /**
      * Returns hash code method open strings.
      *
      * @return hash code method open string
@@ -611,9 +685,10 @@
      */
     public static String getOfMethod(String name, JavaAttributeInfo attr) {
 
-        String attrQuaifiedType = getReturnType(attr);
+        String attrQualifiedType = getReturnType(attr);
+
         return FOUR_SPACE_INDENTATION + PUBLIC + SPACE + STATIC + SPACE + name + SPACE + OF + OPEN_PARENTHESIS
-                + attrQuaifiedType + SPACE + VALUE + CLOSE_PARENTHESIS + SPACE + OPEN_CURLY_BRACKET + NEW_LINE
+                + attrQualifiedType + SPACE + VALUE + CLOSE_PARENTHESIS + SPACE + OPEN_CURLY_BRACKET + NEW_LINE
                 + EIGHT_SPACE_INDENTATION + RETURN + SPACE + NEW + SPACE + name + OPEN_PARENTHESIS + VALUE
                 + CLOSE_PARENTHESIS + SEMI_COLAN + NEW_LINE + FOUR_SPACE_INDENTATION + CLOSE_CURLY_BRACKET + NEW_LINE;
     }
@@ -635,6 +710,69 @@
     }
 
     /**
+     * Returns of method's string and java doc for special type.
+     *
+     * @param attr                   attribute info
+     * @param generatedJavaClassName class name
+     * @return of method's string and java doc for special type
+     */
+    public static String getOfMethodStringAndJavaDoc(JavaAttributeInfo attr, String generatedJavaClassName) {
+
+        String attrType = getReturnType(attr);
+        String attrName = getSmallCase(attr.getAttributeName());
+
+        return getJavaDoc(OF_METHOD, generatedJavaClassName + " for type " + attrName, false)
+                + getOfMethodString(attrType, generatedJavaClassName);
+    }
+
+    /**
+     * Returns of method's string.
+     *
+     * @param type      data type
+     * @param className class name
+     * @return of method's string
+     */
+    private static String getOfMethodString(String type, String className) {
+
+        return FOUR_SPACE_INDENTATION + PUBLIC + SPACE + STATIC + SPACE + className + SPACE + OF + OPEN_PARENTHESIS
+                + type + SPACE + VALUE + CLOSE_PARENTHESIS + SPACE + OPEN_CURLY_BRACKET + NEW_LINE
+                + EIGHT_SPACE_INDENTATION + RETURN + SPACE + NEW + SPACE + className + OPEN_PARENTHESIS + VALUE
+                + CLOSE_PARENTHESIS + SEMI_COLAN + NEW_LINE + FOUR_SPACE_INDENTATION + CLOSE_CURLY_BRACKET;
+    }
+
+    /**
+     * Returns string and java doc for constructor of type class.
+     *
+     * @param attr                   attribute info
+     * @param generatedJavaClassName class name
+     * @return string and java doc for constructor of type class
+     */
+    public static String getTypeConstructorStringAndJavaDoc(JavaAttributeInfo attr, String generatedJavaClassName) {
+
+        String attrType = getReturnType(attr);
+        String attrName = getSmallCase(attr.getAttributeName());
+
+        return getJavaDoc(TYPE_CONSTRUCTOR, generatedJavaClassName + " for type " + attrName, false)
+                + getTypeConstructorString(attrType, attrName, generatedJavaClassName);
+    }
+
+    /**
+     * Returns type constructor string.
+     *
+     * @param type      data type
+     * @param name      attribute name
+     * @param className class name
+     * @return type constructor string
+     */
+    private static String getTypeConstructorString(String type, String name, String className) {
+
+        return FOUR_SPACE_INDENTATION + PUBLIC + SPACE + className + OPEN_PARENTHESIS + type + SPACE + VALUE
+                + CLOSE_PARENTHESIS + SPACE + OPEN_CURLY_BRACKET + NEW_LINE + EIGHT_SPACE_INDENTATION + THIS + PERIOD
+                + name + SPACE + EQUAL + SPACE + VALUE + SEMI_COLAN + NEW_LINE + FOUR_SPACE_INDENTATION
+                + CLOSE_CURLY_BRACKET;
+    }
+
+    /**
      * Returns implementation of get augment info list method of HasAugmentation class.
      *
      * @return implementation of get augment info list method of HasAugmentation class
@@ -660,7 +798,7 @@
         method = method + getOverRideString() + FOUR_SPACE_INDENTATION + PUBLIC + SPACE + VOID + SPACE + "remove"
                 + AUGMENTATION + OPEN_PARENTHESIS + CLOSE_PARENTHESIS + SPACE + OPEN_CURLY_BRACKET + NEW_LINE
                 + EIGHT_SPACE_INDENTATION + GET_METHOD_PREFIX + AUGMENTED_INFO + LIST + OPEN_PARENTHESIS
-                + CLOSE_PARENTHESIS + PERIOD + "clear" + OPEN_PARENTHESIS + CLOSE_PARENTHESIS + SEMI_COLAN + NEW_LINE
+                + CLOSE_PARENTHESIS + PERIOD + CLEAR + OPEN_PARENTHESIS + CLOSE_PARENTHESIS + SEMI_COLAN + NEW_LINE
                 + FOUR_SPACE_INDENTATION + CLOSE_CURLY_BRACKET;
         return method;
     }
diff --git a/src/main/java/org/onosproject/yangutils/translator/tojava/utils/YangJavaModelUtils.java b/src/main/java/org/onosproject/yangutils/translator/tojava/utils/YangJavaModelUtils.java
index 6716251..c706b7d 100644
--- a/src/main/java/org/onosproject/yangutils/translator/tojava/utils/YangJavaModelUtils.java
+++ b/src/main/java/org/onosproject/yangutils/translator/tojava/utils/YangJavaModelUtils.java
@@ -17,7 +17,7 @@
 package org.onosproject.yangutils.translator.tojava.utils;
 
 import java.io.IOException;
-
+import org.onosproject.yangutils.datamodel.HasType;
 import org.onosproject.yangutils.datamodel.YangAugment;
 import org.onosproject.yangutils.datamodel.YangCase;
 import org.onosproject.yangutils.datamodel.YangChoice;
@@ -54,7 +54,7 @@
      * Updates YANG java file package information.
      *
      * @param javaCodeGeneratorInfo YANG java file info node
-     * @param yangPlugin YANG plugin config
+     * @param yangPlugin            YANG plugin config
      * @throws IOException IO operations fails
      */
     private static void updatePackageInfo(JavaCodeGeneratorInfo javaCodeGeneratorInfo, YangPluginConfig yangPlugin)
@@ -72,11 +72,11 @@
      * Updates YANG java file package information for specified package.
      *
      * @param javaCodeGeneratorInfo YANG java file info node
-     * @param yangPlugin YANG plugin config
+     * @param yangPlugin            YANG plugin config
      * @throws IOException IO operations fails
      */
     private static void updatePackageInfo(JavaCodeGeneratorInfo javaCodeGeneratorInfo, YangPluginConfig yangPlugin,
-            String pkg)
+                                          String pkg)
             throws IOException {
         javaCodeGeneratorInfo.getJavaFileInfo()
                 .setJavaName(getCaptialCase(
@@ -113,9 +113,11 @@
         if (javaCodeGeneratorInfo instanceof YangLeavesHolder) {
             javaCodeGeneratorInfo.getTempJavaCodeFragmentFiles()
                     .addCurNodeLeavesInfoToTempFiles((YangNode) javaCodeGeneratorInfo);
+        } else if (javaCodeGeneratorInfo instanceof HasType) {
+            javaCodeGeneratorInfo.getTempJavaCodeFragmentFiles()
+                    .addTypeInfoToTempFiles((HasType) javaCodeGeneratorInfo);
         } else {
-            // TODO: either write a util for ENUM and UNION or, call the
-            // corresponding implementation in ENUM and UNION
+            //TODO throw exception
         }
     }
 
@@ -123,7 +125,7 @@
      * Process generate code entry of YANG node.
      *
      * @param javaCodeGeneratorInfo YANG java file info node
-     * @param codeGenDir code generation directory
+     * @param codeGenDir            code generation directory
      * @throws IOException IO operations fails
      */
     private static void generateTempFiles(JavaCodeGeneratorInfo javaCodeGeneratorInfo, String codeGenDir)
@@ -140,12 +142,12 @@
      * Process generate code entry of YANG node.
      *
      * @param javaCodeGeneratorInfo YANG java file info node
-     * @param yangPlugin YANG plugin config
-     * @param isMultiInstance flag to indicate whether it's a list
+     * @param yangPlugin            YANG plugin config
+     * @param isMultiInstance       flag to indicate whether it's a list
      * @throws IOException IO operations fails
      */
     public static void generateCodeOfNode(JavaCodeGeneratorInfo javaCodeGeneratorInfo, YangPluginConfig yangPlugin,
-            boolean isMultiInstance) throws IOException {
+                                          boolean isMultiInstance) throws IOException {
         if (!(javaCodeGeneratorInfo instanceof YangNode)) {
             // TODO:throw exception
         }
@@ -172,15 +174,32 @@
     }
 
     /**
+     * Process generate code entry of YANG type.
+     *
+     * @param javaCodeGeneratorInfo YANG java file info node
+     * @param yangPlugin            YANG plugin config
+     * @param isMultiInstance       flag to indicate whether it's a list
+     * @throws IOException IO operations fails
+     */
+    public static void generateCodeOfType(JavaCodeGeneratorInfo javaCodeGeneratorInfo, YangPluginConfig yangPlugin,
+                                          boolean isMultiInstance) throws IOException {
+        if (!(javaCodeGeneratorInfo instanceof YangNode)) {
+            // TODO:throw exception
+        }
+        updatePackageInfo(javaCodeGeneratorInfo, yangPlugin);
+        generateTempFiles(javaCodeGeneratorInfo, yangPlugin.getCodeGenDir());
+    }
+
+    /**
      * Process generate code entry of root node.
      *
      * @param javaCodeGeneratorInfo YANG java file info node
-     * @param yangPlugin YANG plugin config
-     * @param rootPkg package of the root node
+     * @param yangPlugin            YANG plugin config
+     * @param rootPkg               package of the root node
      * @throws IOException IO operations fails
      */
     public static void generateCodeOfRootNode(JavaCodeGeneratorInfo javaCodeGeneratorInfo, YangPluginConfig yangPlugin,
-            String rootPkg) throws IOException {
+                                              String rootPkg) throws IOException {
         if (!(javaCodeGeneratorInfo instanceof YangNode)) {
             // TODO:throw exception
         }
diff --git a/src/main/java/org/onosproject/yangutils/utils/UtilConstants.java b/src/main/java/org/onosproject/yangutils/utils/UtilConstants.java
index 3548b43..db3ff8f 100644
--- a/src/main/java/org/onosproject/yangutils/utils/UtilConstants.java
+++ b/src/main/java/org/onosproject/yangutils/utils/UtilConstants.java
@@ -34,18 +34,18 @@
     /**
      * JavaDocs for impl class.
      */
-    public static final String IMPL_CLASS_JAVA_DOC = " * Reperesents the implementation of ";
+    public static final String IMPL_CLASS_JAVA_DOC = " * Represents the implementation of ";
 
     /**
      * JavaDocs for builder class.
      */
-    public static final String BUILDER_CLASS_JAVA_DOC = " * Reperesents the builder implementation of ";
+    public static final String BUILDER_CLASS_JAVA_DOC = " * Represents the builder implementation of ";
 
     /**
      * JavaDocs for interface class.
      */
-    public static final String INTERFACE_JAVA_DOC = " * Abstraction of an entity which Reperesents the"
-            + " functionalities of ";
+    public static final String INTERFACE_JAVA_DOC = " * Abstraction of an entity which represents the"
+            + " functionality of ";
 
     /**
      * JavaDocs for builder interface class.
@@ -148,6 +148,31 @@
     public static final String PERIOD = ".";
 
     /**
+     * Static attribute for parse byte.
+     */
+    public static final String PARSE_BYTE = "parseByte";
+
+    /**
+     * Static attribute for parse short.
+     */
+    public static final String PARSE_SHORT = "parseShort";
+
+    /**
+     * Static attribute for parse int.
+     */
+    public static final String PARSE_INT = "parseInt";
+
+    /**
+     * Static attribute for parse long.
+     */
+    public static final String PARSE_LONG = "parseLong";
+
+    /**
+     * Static attribute for omit null value.
+     */
+    public static final String OMIT_NULL_VALUE_STRING = "omitNullValues()";
+
+    /**
      * Static attribute for colan.
      */
     public static final String COLAN = ":";
@@ -173,9 +198,9 @@
     public static final String SPACE = " ";
 
     /**
-     * Static attribute for tab.
+     * Static attribute for input string.
      */
-    public static final String TAB = "\t";
+    public static final String INPUT = "input";
 
     /**
      * Static attribute for new line.
@@ -223,6 +248,11 @@
     public static final String ADD_STRING = "add";
 
     /**
+     * Static attribute for from syntax.
+     */
+    public static final String FROM_STRING_METHOD_NAME = "fromString";
+
+    /**
      * Static attribute for check not null syntax.
      */
     public static final String CHECK_NOT_NULL_STRING = "checkNotNull";
@@ -333,14 +363,14 @@
     public static final String DIAMOND_CLOSE_BRACKET = ">";
 
     /**
-     * Static attribute for square open bracket syntax.
+     * Static attribute for exception syntax.
      */
-    public static final String SQUARE_OPEN_BRACKET = "[";
+    public static final String EXCEPTION = "Exception";
 
     /**
-     * Static attribute for square close bracket syntax.
+     * Static attribute for exception variable syntax.
      */
-    public static final String SQUARE_CLOSE_BRACKET = "]";
+    public static final String EXCEPTION_VAR = "e";
 
     /**
      * Static attribute for open parenthesis syntax.
@@ -348,6 +378,21 @@
     public static final String OPEN_PARENTHESIS = "(";
 
     /**
+     * Static attribute for clear syntax.
+     */
+    public static final String CLEAR = "clear";
+
+    /**
+     * Static attribute for temp val syntax.
+     */
+    public static final String TMP_VAL = "tmpVal";
+
+    /**
+     * From string parameter name.
+     */
+    public static final String FROM_STRING_PARAM_NAME = "valInString";
+
+    /**
      * Static attribute for close parenthesis syntax.
      */
     public static final String CLOSE_PARENTHESIS = ")";
@@ -378,6 +423,21 @@
     public static final String FOUR_SPACE_INDENTATION = "    ";
 
     /**
+     * Static attribute for not syntax.
+     */
+    public static final String NOT = "!";
+
+    /**
+     * Static attribute for try syntax.
+     */
+    public static final String TRY = "try";
+
+    /**
+     * Static attribute for catch syntax.
+     */
+    public static final String CATCH = "catch";
+
+    /**
      * Static attribute for eight space indentation.
      */
     public static final String EIGHT_SPACE_INDENTATION = FOUR_SPACE_INDENTATION + FOUR_SPACE_INDENTATION;
@@ -518,14 +578,9 @@
     public static final String LONG_WRAPPER = "Long";
 
     /**
-     * Float java built in wrapper type.
+     * YangUint64 java built in wrapper type.
      */
-    public static final String FLOAT_WRAPPER = "Float";
-
-    /**
-     * Double java built in wrapper type.
-     */
-    public static final String DOUBLE_WRAPPER = "Double";
+    public static final String YANG_UINT64 = "YangUint64";
 
     /**
      * List of keywords in java, this is used for checking if the input does not contain these keywords.
@@ -733,92 +788,12 @@
     public static final String AUGMENTED_INFO = "AugmentedInfo";
 
     /**
-     * Static attribute for abstract collection.
-     */
-    public static final String ABSTRACT_COLLECTION = "AbstractCollection";
-
-    /**
      * Static attribute for list.
      */
     public static final String LIST = "List";
 
     /**
-     * Static attribute for linked list.
-     */
-    public static final String LINKED_LIST = "LinkedList";
-
-    /**
      * Static attribute for array list.
      */
     public static final String ARRAY_LIST = "ArrayList";
-
-    /**
-     * Static attribute for abstract list.
-     */
-    public static final String ABSTRACT_LIST = "AbstractList";
-
-    /**
-     * Static attribute for abstract sequential list.
-     */
-    public static final String ABSTRACT_SEQUENTAIL_LIST = "AbstractSequentialList";
-
-    /**
-     * Static attribute for set.
-     */
-    public static final String SET = "Set";
-
-    /**
-     * Static attribute for hash set.
-     */
-    public static final String HASH_SET = "HashSet";
-
-    /**
-     * Static attribute for abstract set.
-     */
-    public static final String ABSTRACT_SET = "AbstractSet";
-
-    /**
-     * Static attribute for linked has set.
-     */
-    public static final String LINKED_HASH_SET = "LinkedHashSet";
-
-    /**
-     * Static attribute for tree set.
-     */
-    public static final String TREE_SET = "TreeSet";
-
-    /**
-     * Static attribute for map.
-     */
-    public static final String MAP = "Map";
-
-    /**
-     * Static attribute for abstract map.
-     */
-    public static final String ABSTRACT_MAP = "AbstractMap";
-
-    /**
-     * Static attribute for hash map.
-     */
-    public static final String HASH_MAP = "HashMap";
-
-    /**
-     * Static attribute for tree map.
-     */
-    public static final String TREE_MAP = "TreeMap";
-
-    /**
-     * Static attribute for concurrent map.
-     */
-    public static final String CONCURRENT_MAP = "ConcurrentMap";
-
-    /**
-     * Static attribute for eventually consistent map.
-     */
-    public static final String EVENTUALLY_CONSISTENT_MAP = "EventuallyConsitentMap";
-
-    /**
-     * Static attribute for stack syntax.
-     */
-    public static final String STACK = "stack";
 }
diff --git a/src/main/java/org/onosproject/yangutils/utils/io/impl/JavaDocGen.java b/src/main/java/org/onosproject/yangutils/utils/io/impl/JavaDocGen.java
index c76ecad..a1cae8e 100644
--- a/src/main/java/org/onosproject/yangutils/utils/io/impl/JavaDocGen.java
+++ b/src/main/java/org/onosproject/yangutils/utils/io/impl/JavaDocGen.java
@@ -23,8 +23,11 @@
 import static org.onosproject.yangutils.utils.UtilConstants.BUILDER_INTERFACE_JAVA_DOC;
 import static org.onosproject.yangutils.utils.UtilConstants.BUILDER_OBJECT;
 import static org.onosproject.yangutils.utils.UtilConstants.FOUR_SPACE_INDENTATION;
+import static org.onosproject.yangutils.utils.UtilConstants.FROM_STRING_METHOD_NAME;
+import static org.onosproject.yangutils.utils.UtilConstants.FROM_STRING_PARAM_NAME;
 import static org.onosproject.yangutils.utils.UtilConstants.IMPL;
 import static org.onosproject.yangutils.utils.UtilConstants.IMPL_CLASS_JAVA_DOC;
+import static org.onosproject.yangutils.utils.UtilConstants.INPUT;
 import static org.onosproject.yangutils.utils.UtilConstants.INTERFACE_JAVA_DOC;
 import static org.onosproject.yangutils.utils.UtilConstants.JAVA_DOC_BUILD;
 import static org.onosproject.yangutils.utils.UtilConstants.JAVA_DOC_BUILD_RETURN;
@@ -45,6 +48,7 @@
 import static org.onosproject.yangutils.utils.UtilConstants.PACKAGE_INFO_JAVADOC;
 import static org.onosproject.yangutils.utils.UtilConstants.PERIOD;
 import static org.onosproject.yangutils.utils.UtilConstants.SPACE;
+import static org.onosproject.yangutils.utils.UtilConstants.STRING_DATA_TYPE;
 import static org.onosproject.yangutils.utils.UtilConstants.VALUE;
 
 /**
@@ -104,11 +108,6 @@
         TYPE_DEF_SETTER_METHOD,
 
         /**
-         * For type def's constructor.
-         */
-        TYPE_DEF_CONSTRUCTOR,
-
-        /**
          * For of method.
          */
         OF_METHOD,
@@ -124,6 +123,16 @@
         CONSTRUCTOR,
 
         /**
+         * For union's from method.
+         */
+        UNION_FROM_METHOD,
+
+        /**
+         * For type constructor.
+         */
+        TYPE_CONSTRUCTOR,
+
+        /**
          * For build.
          */
         BUILD_METHOD
@@ -132,8 +141,8 @@
     /**
      * Returns java docs.
      *
-     * @param type java doc type
-     * @param name name of the YangNode
+     * @param type   java doc type
+     * @param name   name of the YangNode
      * @param isList is list attribute
      * @return javadocs.
      */
@@ -155,8 +164,6 @@
             javaDoc = generateForGetters(name, isList);
         } else if (type.equals(JavaDocType.TYPE_DEF_SETTER_METHOD)) {
             javaDoc = generateForTypeDefSetter(name);
-        } else if (type.equals(JavaDocType.TYPE_DEF_CONSTRUCTOR)) {
-            javaDoc = generateForTypeDefConstructor(name);
         } else if (type.equals(JavaDocType.SETTER_METHOD)) {
             javaDoc = generateForSetters(name, isList);
         } else if (type.equals(JavaDocType.OF_METHOD)) {
@@ -165,6 +172,10 @@
             javaDoc = generateForDefaultConstructors(name);
         } else if (type.equals(JavaDocType.BUILD_METHOD)) {
             javaDoc = generateForBuild(name);
+        } else if (type.equals(JavaDocType.TYPE_CONSTRUCTOR)) {
+            javaDoc = generateForTypeConstructor(name);
+        } else if (type.equals(JavaDocType.UNION_FROM_METHOD)) {
+            javaDoc = generateForUnionFrom(name);
         } else {
             javaDoc = generateForConstructors(name);
         }
@@ -175,7 +186,7 @@
      * Generate javaDocs for getter method.
      *
      * @param attribute attribute
-     * @param isList is list attribute
+     * @param isList    is list attribute
      * @return javaDocs
      */
     private static String generateForGetters(String attribute, boolean isList) {
@@ -198,7 +209,7 @@
      * Generates javaDocs for setter method.
      *
      * @param attribute attribute
-     * @param isList is list attribute
+     * @param isList    is list attribute
      * @return javaDocs
      */
     private static String generateForSetters(String attribute, boolean isList) {
@@ -232,6 +243,22 @@
     }
 
     /**
+     * Generates javaDocs for from method.
+     *
+     * @param attribute attribute
+     * @return javaDocs
+     */
+    private static String generateForUnionFrom(String attribute) {
+
+        return NEW_LINE + FOUR_SPACE_INDENTATION + JAVA_DOC_FIRST_LINE + FOUR_SPACE_INDENTATION + JAVA_DOC_OF
+                + attribute + SPACE + FROM_STRING_METHOD_NAME + SPACE + INPUT + SPACE + STRING_DATA_TYPE + PERIOD
+                + NEW_LINE + FOUR_SPACE_INDENTATION + NEW_LINE_ASTERISK + FOUR_SPACE_INDENTATION + JAVA_DOC_PARAM
+                + FROM_STRING_PARAM_NAME + SPACE + INPUT + SPACE + STRING_DATA_TYPE + PERIOD + NEW_LINE
+                + FOUR_SPACE_INDENTATION + JAVA_DOC_RETURN + OBJECT + SPACE + OF + SPACE + attribute + NEW_LINE
+                + FOUR_SPACE_INDENTATION + JAVA_DOC_END_LINE;
+    }
+
+    /**
      * Generates javaDocs for typedef setter method.
      *
      * @param attribute attribute
@@ -347,4 +374,18 @@
                 + JAVA_DOC_RETURN + JAVA_DOC_BUILD_RETURN + buildName + PERIOD + NEW_LINE + FOUR_SPACE_INDENTATION
                 + JAVA_DOC_END_LINE;
     }
+
+    /**
+     * Generates javaDocs for type constructor.
+     *
+     * @param attribute attribute string
+     * @return javaDocs for type constructor
+     */
+    private static String generateForTypeConstructor(String attribute) {
+
+        return (NEW_LINE + FOUR_SPACE_INDENTATION + JAVA_DOC_FIRST_LINE + FOUR_SPACE_INDENTATION + JAVA_DOC_CONSTRUCTOR
+                + attribute + PERIOD + NEW_LINE + FOUR_SPACE_INDENTATION + NEW_LINE_ASTERISK + FOUR_SPACE_INDENTATION
+                + JAVA_DOC_PARAM + VALUE + SPACE + VALUE + SPACE + OF + SPACE + attribute + NEW_LINE
+                + FOUR_SPACE_INDENTATION + JAVA_DOC_END_LINE);
+    }
 }