get JSON diff > Java

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

import org.json.JSONException;
import org.json.JSONObject;

public class JSONCompare {
	HashMap<String, Object> data;

	public static void main(String[] args) throws JSONException {

		JSONObject json1_new = new org.json.JSONObject(
				"{\"2/1/2017\":\"100\",\"1/1/2016\":\"200\"}");
		JSONObject json1_old = new org.json.JSONObject(
				"{\"2/1/2017\":\"1\",\"1/1/2016\":\"1\",\"1/2/2016\":\"1\"}");

		JSONCompare obj = new JSONCompare();
		System.out.println(obj.updateNewToOldData(json1_old, json1_new));

	}

	public JSONObject updateNewToOldData(JSONObject oldJson, JSONObject newJson)
			throws JSONException {

		data = new HashMap<String, Object>();
		JSONObject json1_new = new JSONObject();
		try {
			Iterator<String> keysIter = newJson.keys();
			while (keysIter.hasNext()) {
				String key = keysIter.next();
				Object value = newJson.get(key);
				data.put(key, value);
			}
			for (String key : data.keySet()) {

				if (oldJson.has(key)) {
					json1_new.put(key, data.get(key));
				}

			}
		} catch (JSONException ex) {

		}
		return json1_new;
	}
}