Thread: Java Problem

So hello guys, im new to Java, still learning so i meant to make like random number generator game where window will be opened and have like 3 buttons if user hits first it move him to mode where he will be guessing numbers from 1-10, if he clicks second button it moves him to window where he will be guessing from numbers from 1-20 etc.So i made 2 files Game.java and Mode.java(Mode 1-10). So here's my code from Game.java

 
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
 
import javax.swing.JFrame;
import javax.swing.UIManager;
import javax.swing.JButton;
import javax.swing.JLabel;
 
public class Game extends JFrame{
 
	private JLabel label1;
	private JLabel label2;
	private JLabel label3;
 
	private JButton button1;
	private JButton button2;
	private JButton button3;
 
	public Game(){
		try{
			UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
		}catch(Exception e){
			e.printStackTrace();
		}
 
		label1 = new JLabel("Choose this mode");
		add(label1);
 
		button1 = new JButton("1-10 Mode");
		button1.addActionListener(new ActionListener(){
			public void actionPerformed(ActionEvent arg){
				dispose(); // Over here i want to open new window where it will be actual game
				new Mode();//But this doesen't work, screen disposes but it dont opens another window
			}
		});
		add(button1);
 
	}
 
	public static void main(String[] args) {
		Game gui = new Game();
		gui.setLayout(new FlowLayout());
 
		gui.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		gui.setSize(300, 100);
		gui.setVisible(true);
		gui.setTitle("Game");
	}
 
}

Here's the code from Mode.java

 
 
import java.awt.FlowLayout;
 
import javax.swing.JFrame;
 
public class Mode extends JFrame{
 
	private static final long serialVersionUID = 1L;
 
	public Mode() {
		Mode mod = new Mode();
		mod.setLayout(new FlowLayout());
		mod.setVisible(true);
		mod.setLocationRelativeTo(null);
		mod.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		mod.setSize(500, 400);
		mod.setTitle("Hello");
 
 
	}
 
}

So screen disposes but don't show any new window and show this error

Exception in thread "AWT-EventQueue-0" java.lang.StackOverflowError
at sun.awt.Win32GraphicsConfig.getBounds(Native Method)
at sun.awt.Win32GraphicsConfig.getBounds(Unknown Source)
at Mode.<init>(Mode.java:10)


Any help would be nice. Greets
By the way, i am using Eclipse IDE

Welcome to the forum! Thanks for taking the time to learn how to post code correctly. If you haven't already, please read this topic to learn other useful info for new members.

A StackOverflow error is typically caused by an infinite recursive call. Note the statement in the Mode() constructor:

Mode mod = new Mode();

What is that going to do?

Alright so i solved this by making new method outside of constructor like private void createWindow() and then calling that into constructor. So, thank you very much i appreciate your answer!

Glad to help. You're welcome.

Update: I like your approach and it may be best for what will follow, but an option was to simply eliminate the mod object, as in:

    public Mode() {
        setLayout(new FlowLayout());
        setVisible(true);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(500, 400);
        setTitle("Hello");
    }