JLabel is not showing

Question

I'm trying to give JLabel in next line, but nothing is happening even my output shows nothing but blank line when I run the code:

Main class:

import javax.swing.JFrame;

public class main {

    public static void main(String[] args){
        test piyu=new test();
        piyu.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        piyu.setSize(300,200);

        piyu.setVisible(true);
    }
}

Test class:

import java.awt.*;
import javax.swing.*;

public class test extends JFrame {

    private JLabel item1,item2;

    public test() {
        super("First Java app");
        JPanel panel=new JPanel();
        panel.setLayout(new GridLayout());
        item1=new JLabel("MY NAME IS XYZ");
        item2=new JLabel("YO");
        item1.setToolTipText("GAME ON");
        panel.add(item1);
        panel.add(item2);
    }
}

Answer 1

You are just missing one line. You never add the JPanel to the JFrame .

class test extends JFrame {

    private JLabel item1,item2;

    public test(){

        super("First Java app");
        JPanel panel=new JPanel();
        panel.setLayout(new GridLayout());
        item1=new JLabel("MY NAME IS XYZ");
        item2=new JLabel("YO");
        item1.setToolTipText("GAME ON");
        panel.add(item1);
        panel.add(item2);
        this.add(panel);

    }
}

Also, note that there is no need to extend JFrame in this case. You could have also written this:

import java.awt.*;
import javax.swing.*;
import javax.swing.JFrame;

public class main {

    public static void main(String[] args){

        JFrame piyu=new JFrame("First Java app");

        JPanel panel=new JPanel();
        JLabel item1,item2;
        panel.setLayout(new GridLayout());
        item1=new JLabel("MY NAME IS XYZ");
        item2=new JLabel("YO");
        item1.setToolTipText("GAME ON");
        panel.add(item1);
        panel.add(item2);
        piyu.add(panel);

        piyu.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        piyu.setSize(300,200);
        piyu.setVisible(true);

    }
}

Answer 2

尝试将JPanel添加到JFrame，并观察其工作:)