diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/BaseFileListener.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/BaseFileListener.java
index f53a767..368f2af 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/BaseFileListener.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/BaseFileListener.java
@@ -19,14 +19,17 @@
 import org.onosproject.yangutils.datamodel.YangModule;
 import org.onosproject.yangutils.datamodel.YangNode;
 import org.onosproject.yangutils.datamodel.YangSubModule;
-import org.onosproject.yangutils.parser.ParsableDataType;
 import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
 import org.onosproject.yangutils.parser.exceptions.ParserException;
 import org.onosproject.yangutils.parser.impl.TreeWalkListener;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation;
+
+import static org.onosproject.yangutils.parser.ParsableDataType.YANGBASE_DATA;
+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.constructListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.*;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsEmpty;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
 
 /*
  * Reference: RFC6020 and YANG ANTLR Grammar
@@ -49,9 +52,8 @@
     }
 
     /**
-     * It is called when parser receives an input matching the grammar
-     * rule (yangfile), perform validations and update the data model
-     * tree.
+     * It is called when parser receives an input matching the grammar rule
+     * (yangfile), perform validations and update the data model tree.
      *
      * @param listener Listener's object.
      * @param ctx context object of the grammar rule.
@@ -59,8 +61,7 @@
     public static void processYangFileEntry(TreeWalkListener listener, GeneratedYangParser.YangfileContext ctx) {
 
         // Check if stack is empty.
-        ListenerValidation.checkStackIsEmpty(listener, ListenerErrorType.INVALID_HOLDER,
-                                             ParsableDataType.YANGBASE_DATA, "", ListenerErrorLocation.ENTRY);
+        checkStackIsEmpty(listener, INVALID_HOLDER, YANGBASE_DATA, "", ENTRY);
 
     }
 
@@ -74,23 +75,17 @@
     public static void processYangFileExit(TreeWalkListener listener, GeneratedYangParser.YangfileContext ctx) {
 
         // Check for stack to be non empty.
-        ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                ParsableDataType.YANGBASE_DATA, "", ListenerErrorLocation.EXIT);
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, YANGBASE_DATA, "", EXIT);
 
         // Data Model tree root node is set.
         if (listener.getParsedDataStack().peek() instanceof YangModule
-                | listener.getParsedDataStack().peek() instanceof YangSubModule) {
+                || listener.getParsedDataStack().peek() instanceof YangSubModule) {
             listener.setRootNode((YangNode) listener.getParsedDataStack().pop());
         } else {
-            throw new ParserException(
-                                      ListenerErrorMessageConstruction
-                                              .constructListenerErrorMessage(ListenerErrorType.INVALID_CHILD,
-                                                                             ParsableDataType.YANGBASE_DATA, "",
-                                                                             ListenerErrorLocation.EXIT));
+            throw new ParserException(constructListenerErrorMessage(INVALID_CHILD, YANGBASE_DATA, "", EXIT));
         }
 
         // Check if stack is empty.
-        ListenerValidation.checkStackIsEmpty(listener, ListenerErrorType.INVALID_HOLDER,
-                                             ParsableDataType.YANGBASE_DATA, "", ListenerErrorLocation.EXIT);
+        checkStackIsEmpty(listener, INVALID_HOLDER, YANGBASE_DATA, "", EXIT);
     }
-}
\ No newline at end of file
+}
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/BelongsToListener.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/BelongsToListener.java
index c8266dc..aec6562 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/BelongsToListener.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/BelongsToListener.java
@@ -19,14 +19,16 @@
 import org.onosproject.yangutils.datamodel.YangBelongsTo;
 import org.onosproject.yangutils.datamodel.YangSubModule;
 import org.onosproject.yangutils.parser.Parsable;
-import org.onosproject.yangutils.parser.ParsableDataType;
 import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
 import org.onosproject.yangutils.parser.exceptions.ParserException;
 import org.onosproject.yangutils.parser.impl.TreeWalkListener;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation;
+
+import static org.onosproject.yangutils.parser.ParsableDataType.BELONGS_TO_DATA;
+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.constructListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.*;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
 
 /*
  * Reference: RFC6020 and YANG ANTLR Grammar
@@ -52,8 +54,9 @@
  */
 
 /**
- * Implements listener based call back function corresponding to the "belongs to"
- * rule defined in ANTLR grammar file for corresponding ABNF rule in RFC 6020.
+ * Implements listener based call back function corresponding to the
+ * "belongs to" rule defined in ANTLR grammar file for corresponding ABNF rule
+ * in RFC 6020.
  */
 public final class BelongsToListener {
 
@@ -64,9 +67,8 @@
     }
 
     /**
-     * It is called when parser receives an input matching the grammar
-     * rule (belongsto), perform validations and update the data model
-     * tree.
+     * It is called when parser receives an input matching the grammar rule
+     * (belongsto), perform validations and update the data model tree.
      *
      * @param listener Listener's object.
      * @param ctx context object of the grammar rule.
@@ -75,10 +77,8 @@
                                              GeneratedYangParser.BelongstoStatementContext ctx) {
 
         // Check for stack to be non empty.
-        ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                ParsableDataType.BELONGS_TO_DATA,
-                                                String.valueOf(ctx.IDENTIFIER().getText()),
-                                                ListenerErrorLocation.ENTRY);
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, BELONGS_TO_DATA, String.valueOf(ctx.IDENTIFIER().getText()),
+                             ENTRY);
 
         YangBelongsTo belongstoNode = new YangBelongsTo();
         belongstoNode.setBelongsToModuleName(String.valueOf(ctx.IDENTIFIER().getText()));
@@ -98,20 +98,16 @@
                                             GeneratedYangParser.BelongstoStatementContext ctx) {
 
         // Check for stack to be non empty.
-        ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                ParsableDataType.BELONGS_TO_DATA,
-                                                String.valueOf(ctx.IDENTIFIER().getText()),
-                                                ListenerErrorLocation.EXIT);
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, BELONGS_TO_DATA, String.valueOf(ctx.IDENTIFIER().getText()),
+                             EXIT);
 
         Parsable tmpBelongstoNode = listener.getParsedDataStack().peek();
         if (tmpBelongstoNode instanceof YangBelongsTo) {
             listener.getParsedDataStack().pop();
 
             // Check for stack to be empty.
-            ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                    ParsableDataType.BELONGS_TO_DATA,
-                                                    String.valueOf(ctx.IDENTIFIER().getText()),
-                                                    ListenerErrorLocation.EXIT);
+            checkStackIsNotEmpty(listener, MISSING_HOLDER, BELONGS_TO_DATA,
+                                 String.valueOf(ctx.IDENTIFIER().getText()), EXIT);
 
             Parsable tmpNode = listener.getParsedDataStack().peek();
             switch (tmpNode.getParsableDataType()) {
@@ -121,22 +117,13 @@
                 break;
             }
             default:
-                throw new ParserException(
-                                          ListenerErrorMessageConstruction
-                                                  .constructListenerErrorMessage(ListenerErrorType.INVALID_HOLDER,
-                                                                                 ParsableDataType.BELONGS_TO_DATA,
-                                                                                 String.valueOf(ctx.IDENTIFIER()
-                                                                                         .getText()),
-                                                                                 ListenerErrorLocation.EXIT));
+                throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, BELONGS_TO_DATA,
+                                                                        String.valueOf(ctx.IDENTIFIER().getText()),
+                                                                        EXIT));
             }
         } else {
-            throw new ParserException(
-                                      ListenerErrorMessageConstruction
-                                              .constructListenerErrorMessage(ListenerErrorType.MISSING_CURRENT_HOLDER,
-                                                                             ParsableDataType.BELONGS_TO_DATA,
-                                                                             String.valueOf(ctx.IDENTIFIER()
-                                                                                     .getText()),
-                                                                             ListenerErrorLocation.EXIT));
+            throw new ParserException(constructListenerErrorMessage(MISSING_CURRENT_HOLDER, BELONGS_TO_DATA,
+                                                                    String.valueOf(ctx.IDENTIFIER().getText()), EXIT));
         }
     }
-}
\ No newline at end of file
+}
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/ContactListener.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/ContactListener.java
index 48174b5..aed2b5e 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/ContactListener.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/ContactListener.java
@@ -19,14 +19,16 @@
 import org.onosproject.yangutils.datamodel.YangModule;
 import org.onosproject.yangutils.datamodel.YangSubModule;
 import org.onosproject.yangutils.parser.Parsable;
-import org.onosproject.yangutils.parser.ParsableDataType;
 import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
 import org.onosproject.yangutils.parser.exceptions.ParserException;
 import org.onosproject.yangutils.parser.impl.TreeWalkListener;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation;
+
+import static org.onosproject.yangutils.parser.ParsableDataType.CONTACT_DATA;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.ENTRY;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction.constructListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.INVALID_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.MISSING_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
 
 /*
  * Reference: RFC6020 and YANG ANTLR Grammar
@@ -81,9 +83,8 @@
     }
 
     /**
-     * It is called when parser receives an input matching the grammar
-     * rule (contact), perform validations and update the data model
-     * tree.
+     * It is called when parser receives an input matching the grammar rule
+     * (contact), perform validations and update the data model tree.
      *
      * @param listener Listener's object.
      * @param ctx context object of the grammar rule.
@@ -91,9 +92,7 @@
     public static void processContactEntry(TreeWalkListener listener, GeneratedYangParser.ContactStatementContext ctx) {
 
         // Check for stack to be non empty.
-        ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                ParsableDataType.CONTACT_DATA,
-                                                String.valueOf(ctx.string().getText()), ListenerErrorLocation.ENTRY);
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, CONTACT_DATA, String.valueOf(ctx.string().getText()), ENTRY);
 
         // Obtain the node of the stack.
         Parsable tmpNode = listener.getParsedDataStack().peek();
@@ -109,12 +108,8 @@
             break;
         }
         default:
-            throw new ParserException(
-                                      ListenerErrorMessageConstruction
-                                              .constructListenerErrorMessage(ListenerErrorType.INVALID_HOLDER,
-                                                                             ParsableDataType.CONTACT_DATA,
-                                                                             String.valueOf(ctx.string().getText()),
-                                                                             ListenerErrorLocation.ENTRY));
+            throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, CONTACT_DATA,
+                                                                    String.valueOf(ctx.string().getText()), ENTRY));
         }
     }
-}
\ No newline at end of file
+}
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/ImportListener.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/ImportListener.java
index 4740699..e47f466 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/ImportListener.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/ImportListener.java
@@ -20,14 +20,16 @@
 import org.onosproject.yangutils.datamodel.YangModule;
 import org.onosproject.yangutils.datamodel.YangSubModule;
 import org.onosproject.yangutils.parser.Parsable;
-import org.onosproject.yangutils.parser.ParsableDataType;
 import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
 import org.onosproject.yangutils.parser.exceptions.ParserException;
 import org.onosproject.yangutils.parser.impl.TreeWalkListener;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation;
+
+import static org.onosproject.yangutils.parser.ParsableDataType.IMPORT_DATA;
+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.constructListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.*;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
 
 /*
  * Reference: RFC6020 and YANG ANTLR Grammar
@@ -64,9 +66,8 @@
     }
 
     /**
-     * It is called when parser receives an input matching the grammar
-     * rule (import), perform validations and update the data model
-     * tree.
+     * It is called when parser receives an input matching the grammar rule
+     * (import), perform validations and update the data model tree.
      *
      * @param listener Listener's object.
      * @param ctx context object of the grammar rule.
@@ -74,10 +75,7 @@
     public static void processImportEntry(TreeWalkListener listener, GeneratedYangParser.ImportStatementContext ctx) {
 
         // Check for stack to be non empty.
-        ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                ParsableDataType.IMPORT_DATA,
-                                                String.valueOf(ctx.IDENTIFIER().getText()),
-                                                ListenerErrorLocation.ENTRY);
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, IMPORT_DATA, String.valueOf(ctx.IDENTIFIER().getText()), ENTRY);
 
         YangImport importNode = new YangImport();
         importNode.setModuleName(String.valueOf(ctx.IDENTIFIER().getText()));
@@ -96,20 +94,15 @@
     public static void processImportExit(TreeWalkListener listener, GeneratedYangParser.ImportStatementContext ctx) {
 
         // Check for stack to be non empty.
-        ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                ParsableDataType.IMPORT_DATA,
-                                                String.valueOf(ctx.IDENTIFIER().getText()),
-                                                ListenerErrorLocation.EXIT);
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, IMPORT_DATA, String.valueOf(ctx.IDENTIFIER().getText()), EXIT);
 
         Parsable tmpImportNode = listener.getParsedDataStack().peek();
         if (tmpImportNode instanceof YangImport) {
             listener.getParsedDataStack().pop();
 
             // Check for stack to be non empty.
-            ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                    ParsableDataType.IMPORT_DATA,
-                                                    String.valueOf(ctx.IDENTIFIER().getText()),
-                                                    ListenerErrorLocation.EXIT);
+            checkStackIsNotEmpty(listener, MISSING_HOLDER, IMPORT_DATA, String.valueOf(ctx.IDENTIFIER().getText()),
+                                 EXIT);
 
             Parsable tmpNode = listener.getParsedDataStack().peek();
             switch (tmpNode.getParsableDataType()) {
@@ -124,22 +117,13 @@
                 break;
             }
             default:
-                throw new ParserException(
-                                          ListenerErrorMessageConstruction
-                                                  .constructListenerErrorMessage(ListenerErrorType.INVALID_HOLDER,
-                                                                                 ParsableDataType.IMPORT_DATA,
-                                                                                 String.valueOf(ctx.IDENTIFIER()
-                                                                                         .getText()),
-                                                                                 ListenerErrorLocation.EXIT));
+                throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, IMPORT_DATA,
+                                                                        String.valueOf(ctx.IDENTIFIER().getText()),
+                                                                        EXIT));
             }
         } else {
-            throw new ParserException(
-                                      ListenerErrorMessageConstruction
-                                              .constructListenerErrorMessage(ListenerErrorType.MISSING_CURRENT_HOLDER,
-                                                                             ParsableDataType.IMPORT_DATA, String
-                                                                                     .valueOf(ctx.IDENTIFIER()
-                                                                                             .getText()),
-                                                                             ListenerErrorLocation.EXIT));
+            throw new ParserException(constructListenerErrorMessage(MISSING_CURRENT_HOLDER, IMPORT_DATA,
+                                                                    String.valueOf(ctx.IDENTIFIER().getText()), EXIT));
         }
     }
-}
\ No newline at end of file
+}
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/IncludeListener.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/IncludeListener.java
index c4678b8..024d811 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/IncludeListener.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/IncludeListener.java
@@ -20,14 +20,16 @@
 import org.onosproject.yangutils.datamodel.YangModule;
 import org.onosproject.yangutils.datamodel.YangSubModule;
 import org.onosproject.yangutils.parser.Parsable;
-import org.onosproject.yangutils.parser.ParsableDataType;
 import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
 import org.onosproject.yangutils.parser.exceptions.ParserException;
 import org.onosproject.yangutils.parser.impl.TreeWalkListener;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation;
+
+import static org.onosproject.yangutils.parser.ParsableDataType.INCLUDE_DATA;
+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.constructListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.*;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
 
 /*
  * Reference: RFC6020 and YANG ANTLR Grammar
@@ -63,9 +65,8 @@
     }
 
     /**
-     * It is called when parser receives an input matching the grammar
-     * rule (include), perform validations and update the data model
-     * tree.
+     * It is called when parser receives an input matching the grammar rule
+     * (include), perform validations and update the data model tree.
      *
      * @param listener Listener's object.
      * @param ctx context object of the grammar rule.
@@ -73,10 +74,8 @@
     public static void processIncludeEntry(TreeWalkListener listener, GeneratedYangParser.IncludeStatementContext ctx) {
 
         // Check for stack to be non empty.
-        ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                ParsableDataType.INCLUDE_DATA,
-                                                String.valueOf(ctx.IDENTIFIER().getText()),
-                                                ListenerErrorLocation.ENTRY);
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, INCLUDE_DATA, String.valueOf(ctx.IDENTIFIER().getText()),
+                             ENTRY);
 
         YangInclude includeNode = new YangInclude();
         includeNode.setSubModuleName(String.valueOf(ctx.IDENTIFIER().getText()));
@@ -94,20 +93,15 @@
     public static void processIncludeExit(TreeWalkListener listener, GeneratedYangParser.IncludeStatementContext ctx) {
 
         // Check for stack to be non empty.
-        ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                ParsableDataType.INCLUDE_DATA,
-                                                String.valueOf(ctx.IDENTIFIER().getText()),
-                                                ListenerErrorLocation.EXIT);
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, INCLUDE_DATA, String.valueOf(ctx.IDENTIFIER().getText()), EXIT);
 
         Parsable tmpIncludeNode = listener.getParsedDataStack().peek();
         if (tmpIncludeNode instanceof YangInclude) {
             listener.getParsedDataStack().pop();
 
             // Check for stack to be non empty.
-            ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                    ParsableDataType.INCLUDE_DATA,
-                                                    String.valueOf(ctx.IDENTIFIER().getText()),
-                                                    ListenerErrorLocation.EXIT);
+            checkStackIsNotEmpty(listener, MISSING_HOLDER, INCLUDE_DATA, String.valueOf(ctx.IDENTIFIER().getText()),
+                                 EXIT);
 
             Parsable tmpNode = listener.getParsedDataStack().peek();
             switch (tmpNode.getParsableDataType()) {
@@ -122,22 +116,13 @@
                 break;
             }
             default:
-                throw new ParserException(
-                                          ListenerErrorMessageConstruction
-                                                  .constructListenerErrorMessage(ListenerErrorType.INVALID_HOLDER,
-                                                                                 ParsableDataType.INCLUDE_DATA,
-                                                                                 String.valueOf(ctx.IDENTIFIER()
-                                                                                         .getText()),
-                                                                                 ListenerErrorLocation.EXIT));
+                throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, INCLUDE_DATA,
+                                                                        String.valueOf(ctx.IDENTIFIER().getText()),
+                                                                        EXIT));
             }
         } else {
-            throw new ParserException(
-                                      ListenerErrorMessageConstruction
-                                              .constructListenerErrorMessage(ListenerErrorType.MISSING_CURRENT_HOLDER,
-                                                                             ParsableDataType.INCLUDE_DATA, String
-                                                                                     .valueOf(ctx.IDENTIFIER()
-                                                                                             .getText()),
-                                                                             ListenerErrorLocation.EXIT));
+            throw new ParserException(constructListenerErrorMessage(MISSING_CURRENT_HOLDER, INCLUDE_DATA,
+                                                                    String.valueOf(ctx.IDENTIFIER().getText()), EXIT));
         }
     }
-}
\ No newline at end of file
+}
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/ModuleListener.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/ModuleListener.java
index cf6309a..2bc8d00 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/ModuleListener.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/ModuleListener.java
@@ -17,14 +17,17 @@
 package org.onosproject.yangutils.parser.impl.listeners;
 
 import org.onosproject.yangutils.datamodel.YangModule;
-import org.onosproject.yangutils.parser.ParsableDataType;
 import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
 import org.onosproject.yangutils.parser.exceptions.ParserException;
 import org.onosproject.yangutils.parser.impl.TreeWalkListener;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation;
+
+import static org.onosproject.yangutils.parser.ParsableDataType.MODULE_DATA;
+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.constructListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.*;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsEmpty;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
 
 /*
  * Reference: RFC6020 and YANG ANTLR Grammar
@@ -57,9 +60,8 @@
     }
 
     /**
-     * It is called when parser receives an input matching the grammar
-     * rule (module), perform validations and update the data model
-     * tree.
+     * It is called when parser receives an input matching the grammar rule
+     * (module), perform validations and update the data model tree.
      *
      * @param listener Listener's object.
      * @param ctx context object of the grammar rule.
@@ -67,9 +69,7 @@
     public static void processModuleEntry(TreeWalkListener listener, GeneratedYangParser.ModuleStatementContext ctx) {
 
         // Check if stack is empty.
-        ListenerValidation
-                .checkStackIsEmpty(listener, ListenerErrorType.INVALID_HOLDER, ParsableDataType.MODULE_DATA,
-                                   String.valueOf(ctx.IDENTIFIER().getText()), ListenerErrorLocation.ENTRY);
+        checkStackIsEmpty(listener, INVALID_HOLDER, MODULE_DATA, String.valueOf(ctx.IDENTIFIER().getText()), ENTRY);
 
         YangModule yangModule = new YangModule();
         yangModule.setName(ctx.IDENTIFIER().getText());
@@ -87,19 +87,11 @@
     public static void processModuleExit(TreeWalkListener listener, GeneratedYangParser.ModuleStatementContext ctx) {
 
         // Check for stack to be non empty.
-        ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                ParsableDataType.MODULE_DATA,
-                                                String.valueOf(ctx.IDENTIFIER().getText()),
-                                                ListenerErrorLocation.EXIT);
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, MODULE_DATA, String.valueOf(ctx.IDENTIFIER().getText()), EXIT);
 
         if (!(listener.getParsedDataStack().peek() instanceof YangModule)) {
-            throw new ParserException(
-                                      ListenerErrorMessageConstruction
-                                              .constructListenerErrorMessage(ListenerErrorType.MISSING_CURRENT_HOLDER,
-                                                                             ParsableDataType.MODULE_DATA, String
-                                                                                     .valueOf(ctx.IDENTIFIER()
-                                                                                             .getText()),
-                                                                             ListenerErrorLocation.EXIT));
+            throw new ParserException(constructListenerErrorMessage(MISSING_CURRENT_HOLDER, MODULE_DATA,
+                                                                    String.valueOf(ctx.IDENTIFIER().getText()), EXIT));
         }
     }
-}
\ No newline at end of file
+}
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/NamespaceListener.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/NamespaceListener.java
index 8386788..db53363 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/NamespaceListener.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/NamespaceListener.java
@@ -19,17 +19,19 @@
 import org.onosproject.yangutils.datamodel.YangModule;
 import org.onosproject.yangutils.datamodel.YangNameSpace;
 import org.onosproject.yangutils.parser.Parsable;
-import org.onosproject.yangutils.parser.ParsableDataType;
 import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
 import org.onosproject.yangutils.parser.exceptions.ParserException;
 import org.onosproject.yangutils.parser.impl.TreeWalkListener;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation;
 
 import java.net.URI;
 
+import static org.onosproject.yangutils.parser.ParsableDataType.NAMESPACE_DATA;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.ENTRY;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction.constructListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.INVALID_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.MISSING_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
+
 /*
  * Reference: RFC6020 and YANG ANTLR Grammar
  *
@@ -65,9 +67,8 @@
     }
 
     /**
-     * It is called when parser receives an input matching the grammar
-     * rule (namespace), perform validations and update the data model
-     * tree.
+     * It is called when parser receives an input matching the grammar rule
+     * (namespace), perform validations and update the data model tree.
      *
      * @param listener Listener's object.
      * @param ctx context object of the grammar rule.
@@ -76,9 +77,7 @@
                                              GeneratedYangParser.NamespaceStatementContext ctx) {
 
         // Check for stack to be non empty.
-        ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                ParsableDataType.NAMESPACE_DATA,
-                                                String.valueOf(ctx.string().getText()), ListenerErrorLocation.ENTRY);
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, NAMESPACE_DATA, String.valueOf(ctx.string().getText()), ENTRY);
 
         if (!validateUriValue(String.valueOf(ctx.string().getText()))) {
             ParserException parserException = new ParserException("Invalid namespace URI");
@@ -98,12 +97,8 @@
             break;
         }
         default:
-            throw new ParserException(
-                                      ListenerErrorMessageConstruction
-                                              .constructListenerErrorMessage(ListenerErrorType.INVALID_HOLDER,
-                                                                             ParsableDataType.NAMESPACE_DATA,
-                                                                             String.valueOf(ctx.string().getText()),
-                                                                             ListenerErrorLocation.ENTRY));
+            throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, NAMESPACE_DATA,
+                                                                    String.valueOf(ctx.string().getText()), ENTRY));
         }
     }
 
@@ -123,4 +118,4 @@
         }
         return true;
     }
-}
\ No newline at end of file
+}
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/OrganizationListener.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/OrganizationListener.java
index edae08e..7260c1c 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/OrganizationListener.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/OrganizationListener.java
@@ -19,14 +19,16 @@
 import org.onosproject.yangutils.datamodel.YangModule;
 import org.onosproject.yangutils.datamodel.YangSubModule;
 import org.onosproject.yangutils.parser.Parsable;
-import org.onosproject.yangutils.parser.ParsableDataType;
 import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
 import org.onosproject.yangutils.parser.exceptions.ParserException;
 import org.onosproject.yangutils.parser.impl.TreeWalkListener;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation;
+
+import static org.onosproject.yangutils.parser.ParsableDataType.ORGANIZATION_DATA;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.ENTRY;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction.constructListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.INVALID_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.MISSING_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
 
 /*
  * Reference: RFC6020 and YANG ANTLR Grammar
@@ -70,8 +72,9 @@
  */
 
 /**
- * Implements listener based call back function corresponding to the "organization"
- * rule defined in ANTLR grammar file for corresponding ABNF rule in RFC 6020.
+ * Implements listener based call back function corresponding to the
+ * "organization" rule defined in ANTLR grammar file for corresponding ABNF rule
+ * in RFC 6020.
  */
 public final class OrganizationListener {
 
@@ -82,9 +85,8 @@
     }
 
     /**
-     * It is called when parser receives an input matching the grammar
-     * rule (organization), perform validations and update the data model
-     * tree.
+     * It is called when parser receives an input matching the grammar rule
+     * (organization), perform validations and update the data model tree.
      *
      * @param listener Listener's object.
      * @param ctx context object of the grammar rule.
@@ -93,9 +95,8 @@
                                                 GeneratedYangParser.OrganizationStatementContext ctx) {
 
         // Check for stack to be non empty.
-        ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                ParsableDataType.ORGANIZATION_DATA,
-                                                String.valueOf(ctx.string().getText()), ListenerErrorLocation.ENTRY);
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, ORGANIZATION_DATA, String.valueOf(ctx.string().getText()),
+                             ENTRY);
 
         // Obtain the node of the stack.
         Parsable tmpNode = listener.getParsedDataStack().peek();
@@ -111,12 +112,8 @@
             break;
         }
         default:
-            throw new ParserException(
-                                      ListenerErrorMessageConstruction
-                                              .constructListenerErrorMessage(ListenerErrorType.INVALID_HOLDER,
-                                                                             ParsableDataType.ORGANIZATION_DATA,
-                                                                             String.valueOf(ctx.string().getText()),
-                                                                             ListenerErrorLocation.ENTRY));
+            throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, ORGANIZATION_DATA,
+                                                                    String.valueOf(ctx.string().getText()), ENTRY));
         }
     }
-}
\ No newline at end of file
+}
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/PrefixListener.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/PrefixListener.java
index 26bc82c..774af7c 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/PrefixListener.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/PrefixListener.java
@@ -20,14 +20,16 @@
 import org.onosproject.yangutils.datamodel.YangImport;
 import org.onosproject.yangutils.datamodel.YangModule;
 import org.onosproject.yangutils.parser.Parsable;
-import org.onosproject.yangutils.parser.ParsableDataType;
 import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
 import org.onosproject.yangutils.parser.exceptions.ParserException;
 import org.onosproject.yangutils.parser.impl.TreeWalkListener;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation;
+
+import static org.onosproject.yangutils.parser.ParsableDataType.PREFIX_DATA;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.ENTRY;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction.constructListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.INVALID_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.MISSING_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
 
 /*
  * Reference: RFC6020 and YANG ANTLR Grammar
@@ -65,9 +67,8 @@
     }
 
     /**
-     * It is called when parser receives an input matching the grammar
-     * rule (prefix),perform validations and update the data model
-     * tree.
+     * It is called when parser receives an input matching the grammar rule
+     * (prefix),perform validations and update the data model tree.
      *
      * @param listener Listener's object.
      * @param ctx context object of the grammar rule.
@@ -75,10 +76,7 @@
     public static void processPrefixEntry(TreeWalkListener listener, GeneratedYangParser.PrefixStatementContext ctx) {
 
         // Check for stack to be non empty.
-        ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                ParsableDataType.PREFIX_DATA,
-                                                String.valueOf(ctx.IDENTIFIER().getText()),
-                                                ListenerErrorLocation.ENTRY);
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, PREFIX_DATA, String.valueOf(ctx.IDENTIFIER().getText()), ENTRY);
 
         // Obtain the node of the stack.
         Parsable tmpNode = listener.getParsedDataStack().peek();
@@ -99,13 +97,8 @@
             break;
         }
         default:
-            throw new ParserException(
-                                      ListenerErrorMessageConstruction
-                                              .constructListenerErrorMessage(ListenerErrorType.INVALID_HOLDER,
-                                                                             ParsableDataType.PREFIX_DATA, String
-                                                                                     .valueOf(ctx.IDENTIFIER()
-                                                                                             .getText()),
-                                                                             ListenerErrorLocation.ENTRY));
+            throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, PREFIX_DATA,
+                                                                    String.valueOf(ctx.IDENTIFIER().getText()), ENTRY));
         }
     }
-}
\ No newline at end of file
+}
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/RevisionDateListener.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/RevisionDateListener.java
index 3f60aef..8cd6d67 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/RevisionDateListener.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/RevisionDateListener.java
@@ -19,14 +19,16 @@
 import org.onosproject.yangutils.datamodel.YangImport;
 import org.onosproject.yangutils.datamodel.YangInclude;
 import org.onosproject.yangutils.parser.Parsable;
-import org.onosproject.yangutils.parser.ParsableDataType;
 import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
 import org.onosproject.yangutils.parser.exceptions.ParserException;
 import org.onosproject.yangutils.parser.impl.TreeWalkListener;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation;
+
+import static org.onosproject.yangutils.parser.ParsableDataType.REVISION_DATE_DATA;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.ENTRY;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction.constructListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.INVALID_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.MISSING_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
 
 /*
  * Reference: RFC6020 and YANG ANTLR Grammar
@@ -57,8 +59,9 @@
  */
 
 /**
- * Implements listener based call back function corresponding to the "revision date"
- * rule defined in ANTLR grammar file for corresponding ABNF rule in RFC 6020.
+ * Implements listener based call back function corresponding to the
+ * "revision date" rule defined in ANTLR grammar file for corresponding ABNF
+ * rule in RFC 6020.
  */
 public final class RevisionDateListener {
 
@@ -69,9 +72,8 @@
     }
 
     /**
-     * It is called when parser receives an input matching the grammar
-     * rule (revision date),perform validations and update the data model
-     * tree.
+     * It is called when parser receives an input matching the grammar rule
+     * (revision date),perform validations and update the data model tree.
      *
      * @param listener Listener's object.
      * @param ctx context object of the grammar rule.
@@ -80,10 +82,8 @@
                                                 GeneratedYangParser.RevisionDateStatementContext ctx) {
 
         // Check for stack to be non empty.
-        ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                ParsableDataType.REVISION_DATE_DATA,
-                                                String.valueOf(ctx.DATE_ARG().getText()),
-                                                ListenerErrorLocation.ENTRY);
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, REVISION_DATE_DATA, String.valueOf(ctx.DATE_ARG().getText()),
+                             ENTRY);
 
         // Obtain the node of the stack.
         Parsable tmpNode = listener.getParsedDataStack().peek();
@@ -99,13 +99,9 @@
             break;
         }
         default:
-            throw new ParserException(
-                                      ListenerErrorMessageConstruction
-                                              .constructListenerErrorMessage(ListenerErrorType.INVALID_HOLDER,
-                                                                             ParsableDataType.REVISION_DATE_DATA,
-                                                                             String.valueOf(ctx.DATE_ARG().getText()),
-                                                                             ListenerErrorLocation.ENTRY));
+            throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, REVISION_DATE_DATA,
+                                                                    String.valueOf(ctx.DATE_ARG().getText()), ENTRY));
         }
     }
     // TODO Implement the DATE_ARG validation as per RFC 6020.
-}
\ No newline at end of file
+}
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/RevisionListener.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/RevisionListener.java
index 0da2f01..7904656 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/RevisionListener.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/RevisionListener.java
@@ -20,14 +20,16 @@
 import org.onosproject.yangutils.datamodel.YangRevision;
 import org.onosproject.yangutils.datamodel.YangSubModule;
 import org.onosproject.yangutils.parser.Parsable;
-import org.onosproject.yangutils.parser.ParsableDataType;
 import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
 import org.onosproject.yangutils.parser.exceptions.ParserException;
 import org.onosproject.yangutils.parser.impl.TreeWalkListener;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation;
+
+import static org.onosproject.yangutils.parser.ParsableDataType.REVISION_DATA;
+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.constructListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.*;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
 
 /*
  * Reference: RFC6020 and YANG ANTLR Grammar
@@ -69,16 +71,21 @@
     private RevisionListener() {
     }
 
+    /**
+     * It is called when parser receives an input matching the grammar rule
+     * (revision),perform validations and update the data model tree.
+     *
+     * @param listener Listener's object.
+     * @param ctx context object of the grammar rule.
+     */
     public static void processRevisionEntry(TreeWalkListener listener,
                                             GeneratedYangParser.RevisionStatementContext ctx) {
 
         // Check for stack to be non empty.
-        ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                ParsableDataType.REVISION_DATA,
-                                                String.valueOf(ctx.DATE_ARG().getText()),
-                                                ListenerErrorLocation.ENTRY);
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, REVISION_DATA, String.valueOf(ctx.DATE_ARG().getText()), ENTRY);
 
-        // Validate for reverse chronological order of revision & for revision value.
+        // Validate for reverse chronological order of revision & for revision
+        // value.
         if (!validateRevision(listener, ctx)) {
             return;
             // TODO to be implemented.
@@ -97,23 +104,19 @@
      * @param listener Listener's object.
      * @param ctx context object of the grammar rule.
      */
-    public static void processRevisionExit(TreeWalkListener listener,
-                                           GeneratedYangParser.RevisionStatementContext ctx) {
+    public static void processRevisionExit(TreeWalkListener listener, GeneratedYangParser.RevisionStatementContext
+            ctx) {
 
         // Check for stack to be non empty.
-        ListenerValidation
-                .checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER, ParsableDataType.REVISION_DATA,
-                                      String.valueOf(ctx.DATE_ARG().getText()), ListenerErrorLocation.EXIT);
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, REVISION_DATA, String.valueOf(ctx.DATE_ARG().getText()), EXIT);
 
         Parsable tmpRevisionNode = listener.getParsedDataStack().peek();
         if (tmpRevisionNode instanceof YangRevision) {
             listener.getParsedDataStack().pop();
 
             // Check for stack to be non empty.
-            ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                    ParsableDataType.REVISION_DATA,
-                                                    String.valueOf(ctx.DATE_ARG().getText()),
-                                                    ListenerErrorLocation.EXIT);
+            checkStackIsNotEmpty(listener, MISSING_HOLDER, REVISION_DATA, String.valueOf(ctx.DATE_ARG().getText()),
+                                 EXIT);
 
             Parsable tmpNode = listener.getParsedDataStack().peek();
             switch (tmpNode.getParsableDataType()) {
@@ -128,22 +131,13 @@
                 break;
             }
             default:
-                throw new ParserException(
-                                          ListenerErrorMessageConstruction
-                                                  .constructListenerErrorMessage(ListenerErrorType.INVALID_HOLDER,
-                                                                                 ParsableDataType.REVISION_DATA,
-                                                                                 String.valueOf(ctx.DATE_ARG()
-                                                                                         .getText()),
-                                                                                 ListenerErrorLocation.EXIT));
+                throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, REVISION_DATA,
+                                                                        String.valueOf(ctx.DATE_ARG().getText()),
+                                                                        EXIT));
             }
         } else {
-            throw new ParserException(
-                                      ListenerErrorMessageConstruction
-                                              .constructListenerErrorMessage(ListenerErrorType.MISSING_CURRENT_HOLDER,
-                                                                             ParsableDataType.REVISION_DATA, String
-                                                                                     .valueOf(ctx.DATE_ARG()
-                                                                                             .getText()),
-                                                                             ListenerErrorLocation.EXIT));
+            throw new ParserException(constructListenerErrorMessage(MISSING_CURRENT_HOLDER, REVISION_DATA,
+                                                                    String.valueOf(ctx.DATE_ARG().getText()), EXIT));
         }
     }
 
@@ -159,4 +153,4 @@
         // TODO to be implemented
         return true;
     }
-}
\ No newline at end of file
+}
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/SubModuleListener.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/SubModuleListener.java
index 3f6fc40..42c753c 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/SubModuleListener.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/SubModuleListener.java
@@ -17,14 +17,17 @@
 package org.onosproject.yangutils.parser.impl.listeners;
 
 import org.onosproject.yangutils.datamodel.YangSubModule;
-import org.onosproject.yangutils.parser.ParsableDataType;
 import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
 import org.onosproject.yangutils.parser.exceptions.ParserException;
 import org.onosproject.yangutils.parser.impl.TreeWalkListener;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation;
+
+import static org.onosproject.yangutils.parser.ParsableDataType.SUB_MODULE_DATA;
+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.constructListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.*;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsEmpty;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
 
 /*
  * Reference: RFC6020 and YANG ANTLR Grammar
@@ -58,9 +61,8 @@
     }
 
     /**
-     * It is called when parser receives an input matching the grammar
-     * rule (sub module), perform validations and update the data model
-     * tree.
+     * It is called when parser receives an input matching the grammar rule (sub
+     * module), perform validations and update the data model tree.
      *
      * @param listener Listener's object.
      * @param ctx context object of the grammar rule.
@@ -69,9 +71,8 @@
                                              GeneratedYangParser.SubModuleStatementContext ctx) {
 
         // Check if stack is empty.
-        ListenerValidation
-                .checkStackIsEmpty(listener, ListenerErrorType.INVALID_HOLDER, ParsableDataType.SUB_MODULE_DATA,
-                                   String.valueOf(ctx.IDENTIFIER().getText()), ListenerErrorLocation.ENTRY);
+        checkStackIsEmpty(listener, INVALID_HOLDER, SUB_MODULE_DATA, String.valueOf(ctx.IDENTIFIER().getText()),
+                          ENTRY);
 
         YangSubModule yangSubModule = new YangSubModule();
         yangSubModule.setName(ctx.IDENTIFIER().getText());
@@ -90,19 +91,12 @@
                                             GeneratedYangParser.SubModuleStatementContext ctx) {
 
         // Check for stack to be non empty.
-        ListenerValidation.checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER,
-                                                ParsableDataType.SUB_MODULE_DATA,
-                                                String.valueOf(ctx.IDENTIFIER().getText()),
-                                                ListenerErrorLocation.EXIT);
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, SUB_MODULE_DATA, String.valueOf(ctx.IDENTIFIER().getText()),
+                             EXIT);
 
         if (!(listener.getParsedDataStack().peek() instanceof YangSubModule)) {
-            throw new ParserException(
-                                      ListenerErrorMessageConstruction
-                                              .constructListenerErrorMessage(ListenerErrorType.MISSING_CURRENT_HOLDER,
-                                                                             ParsableDataType.SUB_MODULE_DATA,
-                                                                             String.valueOf(ctx.IDENTIFIER()
-                                                                                     .getText()),
-                                                                             ListenerErrorLocation.EXIT));
+            throw new ParserException(constructListenerErrorMessage(MISSING_CURRENT_HOLDER, SUB_MODULE_DATA,
+                                                                    String.valueOf(ctx.IDENTIFIER().getText()), EXIT));
         }
     }
-}
\ No newline at end of file
+}
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/VersionListener.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/VersionListener.java
index ae9389f..f9d904d 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/VersionListener.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/VersionListener.java
@@ -19,14 +19,16 @@
 import org.onosproject.yangutils.datamodel.YangModule;
 import org.onosproject.yangutils.datamodel.YangSubModule;
 import org.onosproject.yangutils.parser.Parsable;
-import org.onosproject.yangutils.parser.ParsableDataType;
 import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
 import org.onosproject.yangutils.parser.exceptions.ParserException;
 import org.onosproject.yangutils.parser.impl.TreeWalkListener;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType;
-import org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation;
+
+import static org.onosproject.yangutils.parser.ParsableDataType.VERSION_DATA;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.ENTRY;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction.constructListenerErrorMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.INVALID_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.MISSING_HOLDER;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerValidation.checkStackIsNotEmpty;
 
 /*
  * Reference: RFC6020 and YANG ANTLR Grammar
@@ -73,9 +75,8 @@
     }
 
     /**
-     * It is called when parser receives an input matching the grammar
-     * rule (version), perform validations and update the data model
-     * tree.
+     * It is called when parser receives an input matching the grammar rule
+     * (version), perform validations and update the data model tree.
      *
      * @param listener Listener's object.
      * @param ctx context object of the grammar rule.
@@ -84,9 +85,7 @@
                                            GeneratedYangParser.YangVersionStatementContext ctx) {
 
         // Check for stack to be non empty.
-        ListenerValidation
-                .checkStackIsNotEmpty(listener, ListenerErrorType.MISSING_HOLDER, ParsableDataType.VERSION_DATA,
-                                      String.valueOf(ctx.INTEGER().getText()), ListenerErrorLocation.ENTRY);
+        checkStackIsNotEmpty(listener, MISSING_HOLDER, VERSION_DATA, String.valueOf(ctx.INTEGER().getText()), ENTRY);
 
         Integer version = Integer.valueOf(ctx.INTEGER().getText());
         if (!isVersionValid(version)) {
@@ -110,10 +109,8 @@
             break;
         }
         default:
-            throw new ParserException(ListenerErrorMessageConstruction.
-                    constructListenerErrorMessage(ListenerErrorType.INVALID_HOLDER,
-                            ParsableDataType.VERSION_DATA, String.valueOf(ctx.INTEGER().getText()),
-                            ListenerErrorLocation.ENTRY));
+            throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER, VERSION_DATA,
+                                                                    String.valueOf(ctx.INTEGER().getText()), ENTRY));
         }
     }
 
@@ -126,4 +123,4 @@
     private static boolean isVersionValid(Integer version) {
         return version == 1;
     }
-}
\ No newline at end of file
+}
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/parserutils/ListenerErrorMessageConstruction.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/parserutils/ListenerErrorMessageConstruction.java
index 1de8f44..1ef25e3 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/parserutils/ListenerErrorMessageConstruction.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/parserutils/ListenerErrorMessageConstruction.java
@@ -18,6 +18,10 @@
 
 import org.onosproject.yangutils.parser.ParsableDataType;
 
+import static org.onosproject.yangutils.parser.ParsableDataType.getParsableDataType;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorLocation.getErrorLocationMessage;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorType.getErrorType;
+
 /**
  * It's a utility to help construct detailed error message.
  */
@@ -30,13 +34,15 @@
     }
 
     /**
-     * Constructs message for error with extended information and returns the same.
+     * Constructs message for error with extended information and returns the
+     * same.
      *
-     * @param errorType            error type needs to be set in error message.
-     * @param parsableDataType     type of parsable data in which error occurred.
-     * @param parsableDataTypeName identifier/string of parsable data type in which error occurred.
-     * @param errorLocation        location where error occurred.
-     * @param extendedErrorInformation  extended error information.
+     * @param errorType error type needs to be set in error message.
+     * @param parsableDataType type of parsable data in which error occurred.
+     * @param parsableDataTypeName identifier/string of parsable data type in
+     *            which error occurred.
+     * @param errorLocation location where error occurred.
+     * @param extendedErrorInformation extended error information.
      * @return constructed error message.
      */
     public static String constructExtendedListenerErrorMessage(ListenerErrorType errorType,
@@ -46,16 +52,21 @@
                                                                String extendedErrorInformation) {
         String newErrorMessage;
         newErrorMessage = constructListenerErrorMessage(errorType, parsableDataType, parsableDataTypeName,
-                errorLocation) + "\n" + "Error Information: " + extendedErrorInformation;
+                                                        errorLocation)
+                + "\n"
+                + "Error Information: "
+                + extendedErrorInformation;
         return newErrorMessage;
     }
 
     /**
-     * Constructs message for error during listener based tree walk and returns the same.
+     * Constructs message for error during listener based tree walk and returns
+     * the same.
      *
      * @param errorType error type needs to be set in error message.
      * @param parsableDataType type of parsable data in which error occurred.
-     * @param parsableDataTypeName identifier/string of parsable data type in which error occurred.
+     * @param parsableDataTypeName identifier/string of parsable data type in
+     *            which error occurred.
      * @param errorLocation location where error occurred.
      * @return constructed error message.
      */
@@ -66,9 +77,8 @@
 
         String errorMessage;
 
-        errorMessage = "Internal parser error detected: " + ListenerErrorType.getErrorType(errorType) + " "
-                + ParsableDataType.getParsableDataType(parsableDataType);
-
+        errorMessage = "Internal parser error detected: " + getErrorType(errorType) + " "
+                + getParsableDataType(parsableDataType);
 
         if (!parsableDataTypeName.isEmpty()) {
             errorMessage = errorMessage + " \"" + parsableDataTypeName + "\" ";
@@ -76,7 +86,7 @@
             errorMessage = errorMessage + " ";
 
         }
-        errorMessage = errorMessage + ListenerErrorLocation.getErrorLocationMessage(errorLocation) + " processing.";
+        errorMessage = errorMessage + getErrorLocationMessage(errorLocation) + " processing.";
         return errorMessage;
     }
-}
\ No newline at end of file
+}
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/parserutils/ListenerValidation.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/parserutils/ListenerValidation.java
index 4399cc5..226a530 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/parserutils/ListenerValidation.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/parserutils/ListenerValidation.java
@@ -19,6 +19,7 @@
 import org.onosproject.yangutils.parser.ParsableDataType;
 import org.onosproject.yangutils.parser.exceptions.ParserException;
 import org.onosproject.yangutils.parser.impl.TreeWalkListener;
+import static org.onosproject.yangutils.parser.impl.parserutils.ListenerErrorMessageConstruction.constructListenerErrorMessage;
 
 /**
  * It's a utility to carry out listener validation.
@@ -37,19 +38,21 @@
      * @param listener Listener's object.
      * @param errorType error type needs to be set in error message.
      * @param parsableDataType type of parsable data in which error occurred.
-     * @param parsableDataTypeName name of parsable data type in which error occurred.
+     * @param parsableDataTypeName name of parsable data type in which error
+     *            occurred.
      * @param errorLocation location where error occurred.
      */
     public static void checkStackIsNotEmpty(TreeWalkListener listener, ListenerErrorType errorType,
-                                               ParsableDataType parsableDataType, String parsableDataTypeName,
-                                               ListenerErrorLocation errorLocation) {
+                                            ParsableDataType parsableDataType, String parsableDataTypeName,
+                                            ListenerErrorLocation errorLocation) {
         if (listener.getParsedDataStack().empty()) {
             /*
-             * If stack is empty it indicates error condition, value of parsableDataTypeName will be null in case there
-             * is no name attached to parsable data type.
+             * If stack is empty it indicates error condition, value of
+             * parsableDataTypeName will be null in case there is no name
+             * attached to parsable data type.
              */
-            String message = ListenerErrorMessageConstruction.constructListenerErrorMessage(errorType, parsableDataType,
-                    parsableDataTypeName, errorLocation);
+            String message = constructListenerErrorMessage(errorType, parsableDataType, parsableDataTypeName,
+                                                           errorLocation);
             throw new ParserException(message);
         }
     }
@@ -60,22 +63,24 @@
      * @param listener Listener's object.
      * @param errorType error type needs to be set in error message.
      * @param parsableDataType type of parsable data in which error occurred.
-     * @param parsableDataTypeName name of parsable data type in which error occurred.
+     * @param parsableDataTypeName name of parsable data type in which error
+     *            occurred.
      * @param errorLocation location where error occurred.
      */
 
     public static void checkStackIsEmpty(TreeWalkListener listener, ListenerErrorType errorType,
-                                            ParsableDataType parsableDataType, String parsableDataTypeName,
-                                            ListenerErrorLocation errorLocation) {
+                                         ParsableDataType parsableDataType, String parsableDataTypeName,
+                                         ListenerErrorLocation errorLocation) {
 
         if (!listener.getParsedDataStack().empty()) {
             /*
-             * If stack is empty it indicates error condition, value of parsableDataTypeName will be null in case there
-             * is no name attached to parsable data type.
+             * If stack is empty it indicates error condition, value of
+             * parsableDataTypeName will be null in case there is no name
+             * attached to parsable data type.
              */
-            String message = ListenerErrorMessageConstruction.constructListenerErrorMessage(errorType, parsableDataType,
-                    parsableDataTypeName, errorLocation);
+            String message = constructListenerErrorMessage(errorType, parsableDataType, parsableDataTypeName,
+                                                           errorLocation);
             throw new ParserException(message);
         }
     }
-}
\ No newline at end of file
+}