In this example we will show you how to convert java object to JSON using Gson library. Gson is a Java library that can be used to convert Java Objects into their JSON representation. It can also be used to convert a JSON string to an equivalent Java object.

Firs of all we need to add following dependency into the maven pom.xml

<dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>2.8.0</version>
</dependency>

So to convert the java object into its JSON representation we need to do following:

Gson gson = new GsonBuilder().create();
String json = gson.toJson(object);

And the full example:

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

public class ModelToJsonExample {

    private static class User {

        private String name;

        private String emailAddress;

        public User(String name, String emailAddress) {
            this.name = name;
            this.emailAddress = emailAddress;
        }

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        public String getEmailAddress() {
            return emailAddress;
        }

        public void setEmailAddress(String emailAddress) {
            this.emailAddress = emailAddress;
        }
    }

    public static void main(String[] args) {

        User user = new User("testName", "testEmailAddress");
        Gson gson = new GsonBuilder().create();
        String json = gson.toJson(user);
        System.out.println(json);

    }
}

And the output should be:

{"name":"testName","emailAddress":"testEmailAddress"}