1import org.json.simple.JSONObject;
2import org.json.simple.parser.JSONParser;
3import org.json.simple.parser.ParseException;
4
5public class TestJSON {
6
7	public static void main(String[] args) {
8
9		JSONObject jObject = new JSONObject();
10
11		jObject.put("EmployeeId", new Integer(121));
12		jObject.put("Name", "Ramesh");
13		jObject.put("Salary", new Double(15000.00));
14		jObject.put("isPermanent", new Boolean(true));
15		jObject.put("Nickname", null);
16		
17		//convert from JSONObject to JSON string
18		String jsonText = jObject.toJSONString();
19
20		System.out.println(jsonText);
21
22		JSONParser parser = new JSONParser();
23		
24		//convert from JSON string to JSONObject
25		JSONObject newJObject = null;
26		try {
27			newJObject = (JSONObject) parser.parse(jsonText);
28		} catch (ParseException e) {
29			e.printStackTrace();
30		}
31
32		System.out.println(newJObject.get("EmployeeId"));
33		System.out.println(newJObject.get("Name"));
34		System.out.println(newJObject.get("Salary"));
35		System.out.println(newJObject.get("isPermanent"));
36		System.out.println(newJObject.get("Nickname"));
37	}
38}

1try {
2     JSONObject jsonObject = new JSONObject("{\"phonetype\":\"N95\",\"cat\":\"WP\"}");
3}catch (JSONException err){
4     Log.d("Error", err.toString());
5}
6

1Jackson Data-bind depdendency that take care of 
2Converting between 
3JSON to Java Object 
4and 
5Java Object to JSON
6
7<dependency>
8    <groupId>com.fasterxml.jackson.core</groupId>
9    <artifactId>jackson-databind</artifactId>
10    <version>2.12.0</version>
11</dependency>

1I add GSON dependency in my POM --> It’s a json parser. That is
2used to convert from java object to json and from json to java
3object
4SERIALIZATION: CONVERT JAVA OBJECT -> JSON
5DE-SERIALIZATION: CONVERT JSON -> JAVA OBJECT