diff --git a/apps/yms/app/src/main/java/org/onosproject/yms/app/yob/YobConstants.java b/apps/yms/app/src/main/java/org/onosproject/yms/app/yob/YobConstants.java
index 6ed14267..cf2638e 100644
--- a/apps/yms/app/src/main/java/org/onosproject/yms/app/yob/YobConstants.java
+++ b/apps/yms/app/src/main/java/org/onosproject/yms/app/yob/YobConstants.java
@@ -30,12 +30,16 @@
     static final String DEFAULT = "Default";
     static final String ADD_TO = "addTo";
     static final String VALUE_OF = "valueOf";
-    static final String OPERATION_TYPE = "onosYangNodeOperationType";
-    static final String OP_TYPE = "OnosYangNodeOperationType";
+    static final String OP_TYPE = "OpType";
+    static final String ONOS_YANG_OP_TYPE = "OnosYangOpType";
     static final String OF = "of";
     static final String PERIOD = ".";
     static final String SPACE = " ";
     static final String ADD_AUGMENT_METHOD = "addYangAugmentedInfo";
+    static final String YANG = "yang";
+    static final String JAVA_LANG = "java.lang";
+    static final String LEAF_IDENTIFIER = "LeafIdentifier";
+    static final String SELECT_LEAF = "selectLeaf";
 
     //Error strings
     static final String E_NO_HANDLE_FOR_YDT = "No handler for YDT node";
@@ -78,6 +82,10 @@
             "Builder is not yet set, cannot fetch it";
     static final String E_BUILT_OBJ_IS_NOT_SET =
             "Built object is not set";
+    static final String E_OBJ_IS_ALREADY_BUILT_NOT_SET =
+            "Object is already built, cannot set builder";
+    static final String E_BUILDER_IS_NOT_ALREADY_SET =
+            "Builder is not already set";
     static final String E_OBJ_IS_NOT_SET_NOT_FETCH =
             "Builder is not yet set, cannot fetch it";
     static final String E_OBJ_IS_ALREADY_BUILT_NOT_BUILD =
@@ -88,4 +96,6 @@
             "YANG data tree is missing the data required for YOB";
     static final String E_INVALID_DATA_TREE =
             "YANG tree does not have a application root";
+    static final String E_INVALID_EMPTY_DATA =
+            "Value for empty data type is invalid";
 }