How to write a JSON file using java

download json-simple jar package

https://repo1.maven.org/maven2/com/googlecode/json-simple/json-simple/1.1.1/
https://cliftonlabs.github.io/json-simple/

// Java read write json example
import java.io.FileWriter;
import java.io.IOException;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
 
public class WriteJSONExample
{
    @SuppressWarnings("unchecked")
    public static void main( String[] args )
    {
        //First Employee
        JSONObject employeeDetails = new JSONObject();
        employeeDetails.put("firstName", "HymanLi");
        employeeDetails.put("lastName", "Gupta");
        employeeDetails.put("website", "howtodoinjava.com");
         
        JSONObject employeeObject = new JSONObject(); 
        employeeObject.put("employee", employeeDetails);
         
        //Second Employee
        JSONObject employeeDetails2 = new JSONObject();
        employeeDetails2.put("firstName", "BobRobert");
        employeeDetails2.put("lastName", "Schultz");
        employeeDetails2.put("website", "lautturi.com");
         
        JSONObject employeeObject2 = new JSONObject(); 
        employeeObject2.put("employee", employeeDetails2);
         
        //Add employees to list
        JSONArray employeeList = new JSONArray();
        employeeList.add(employeeObject);
        employeeList.add(employeeObject2);
         
        //Write JSON file
        try (FileWriter file = new FileWriter("employees.json")) {
            //We can write any JSONArray or JSONObject instance to the file
            file.write(employeeList.toJSONString()); 
            file.flush();
 
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}