yang choice case translator + whitebox fix

Change-Id: I96f1855bc71a002335946150b51e911ae6ac2fb2
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 ec58b26..9fa13d4 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
@@ -109,7 +109,7 @@
         }
         String def = PUBLIC + SPACE + INTERFACE + SPACE + yangName + SPACE + EXTEND + SPACE;
         for (String extend : getExtendsList()) {
-            def = def + extend + COMMA;
+            def = def + extend + COMMA + SPACE;
         }
         def = trimAtLast(def, COMMA);