Ex2.java

Gson gson = new Gson();

System.out.println("Default behaviour ");
GsonBuilder gsonBuilder = new GsonBuilder();

Gson prettyGson = gsonBuilder.setPrettyPrinting().create();
String json = prettyGson.toJson(new Developer());
System.out.println(json);

System.out.println("Including the nulls ");
Gson includeNullsGson = gsonBuilder.serializeNulls().create();
String json2 = includeNullsGson.toJson(new Developer());
System.out.println(json2);