How to create JSON response object

/**
 * Customer class having Customer Details
 */


public class Customer {
 String f_name="";
 String l_name="";
 String address="";
 int age=0;
 
//Constructors 

public Customer(String f_name, String l_name, String address, int age) {
 super();
 this.f_name = f_name;
 this.l_name = l_name;
 this.address = address;
 this.age = age;
}

//Getters and Setters 


public String getF_name() {
 return f_name;
}
public void setF_name(String f_name) {
 this.f_name = f_name;
}
public String getL_name() {
 return l_name;
}
public void setL_name(String l_name) {
 this.l_name = l_name;
}
public String getAddress() {
 return address;
}
public void setAddress(String address) {
 this.address = address;
}
public int getAge() {
 return age;
}
public void setAge(int age) {
 this.age = age;
}
 
}



import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.json.simple.JSONObject;


/**
 * Servlet implementation class ConvertJAva2JSON
 */

public class ConvertJava2JSON extends HttpServlet {
 private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public ConvertJava2JSON() {
        super();
      
    }

 /**
  * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
  */
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  
  process(request, response);
 }

 /**
  * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
  */
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  
  process(request, response);
 }

 
 
 private void process(HttpServletRequest request,
   HttpServletResponse response) {
  
  JSONObject cusObj = new JSONObject();
  Customer cus=new Customer("Ramesh","Das","BBSR",19);
  cusObj=generateJSONObject(cus);
  if(cusObj!= null)
   sendJSONResponse(response,cusObj);
  else
   System.out.println("No Result");
  
  
  
 }
 /**
  * This method writes  json object to the response
  * @param response
  * @param cusObj
  */
 private void sendJSONResponse(HttpServletResponse response,
   JSONObject cusObj) {
  try{
   response.getWriter().print("CustomerDetails" +"("+cusObj+")");
  }
  catch(Exception ex)
  {
   System.out.println(ex.getMessage());
  }
  
 }
 /**
  * This method returns the json object 
  * and provide the Customer Object  to the method -'generateJSONComponent' and returns a JSONObject object to process method
  * @param Customer
  * @return JSONObject
  */
 @SuppressWarnings("unchecked")
 private JSONObject generateJSONObject(Customer cus) {
  JSONObject cusObj=new JSONObject();
  cusObj.put("First Name", cus.getF_name());
  cusObj.put("Last Name", cus.getL_name());
  cusObj.put("Address", cus.getAddress());
  cusObj.put("Age", cus.getAge());
  return cusObj;
  
 }

}