JavaのGsonライブラリを使用してマップをJSONに変換する

import java.lang.reflect.*;
import java.util.*;
import com.google.gson.*;
import com.google.gson.reflect.*;
public class ConverMapToJsonTest {
   public static void main(String args[]) {
      SortedMap<String, String> data= new TreeMap<String, String>();
      data.put("Raja", "Java");
      data.put("Ravi", "SAP");
      data.put("Surya", "Python");
      data.put("Kiran", "Scala");
      data.put("Vamsi", "Selenium");
      Gson gson = new Gson();
      Type gsonType = new TypeToken(){}.getType();
      String gsonString = gson.toJson(data, gsonType);
      System.out.println(gsonString);
   }
}

{"Kiran":"Scala","Raja":"Java","Ravi":"SAP","Surya":"Python","Vamsi":"Selenium"}