Update Type entity to store empty lists instead of null.

Signed-off-by: Rahul Krishna <i.m.ralk@gmail.com>

Author: rahlk

src/main/java/com/ibm/cldk/entities/Type.java

@@ -2,6 +2,8 @@
 
 import lombok.Data;
 
+import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
@@ -15,15 +17,15 @@ public class Type {
     private boolean isInterface;
     private boolean isInnerClass;
     private boolean isLocalClass;
-    private List<String> extendsList;
+    private List<String> extendsList = new ArrayList<>();
     private String comment;
-    private List<String> implementsList;
-    private List<String> modifiers;
-    private List<String> annotations;
+    private List<String> implementsList = new ArrayList<>();
+    private List<String> modifiers = new ArrayList<>();
+    private List<String> annotations = new ArrayList<>();
     private String parentType;
-    private List<String> nestedTypeDeclarations;
-    private Map<String, Callable> callableDeclarations;
-    private List<Field> fieldDeclarations;
-    private List<EnumConstant> enumConstants;
+    private List<String> nestedTypeDeclarations = new ArrayList<>();
+    private Map<String, Callable> callableDeclarations = new HashMap<>();
+    private List<Field> fieldDeclarations = new ArrayList<>();
+    private List<EnumConstant> enumConstants = new ArrayList<>();
     private boolean isEntrypointClass = false;
 }