Hi,

You can use the com.google.gson.Gson class of Google Gson library.

Then use following method to covert it to JSON String:

String json = gsonFormatted.toJson(map);

Here is full example of the program:

package net.roseindia;

import java.util.HashMap;
import java.util.Map;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

public class JsonFormattedOutput {

    public static void main(String[] args) {

        Map<String, String> map = new HashMap<String, String>();

        map.put("ProductID", "C0001");
        map.put("Name", "Mouse");
        map.put("Price", "250");

        Gson gsonFormatted = new GsonBuilder().setPrettyPrinting().create();
        String json = gsonFormatted.toJson(map);
        System.out.println("JSON String:");
        System.out.println(json);
    }
}

Here is the output of the program:

JSON String:

{
  "Price": "250",
  "ProductID": "C0001",
  "Name": "Mouse"
}

Thanks