how do i fullscreen my jframe?

[manic bobcat]

i want to set my jframe and jpanel to fullscreen but i cant get it to work. i tried frame.setExtendedState(frame.MAXIMIZED_BOTH);
but it didnt work at all.

[steep fossil]

<@&987246487241105418> please have a look, thanks.

[manic bobcat]

these are the classes where i create and use jframe/jpanel

[steep fossil]

I uploaded your attachments as Gist. This makes them more accessible, for example to mobile users.

[grim grove]

https://stackoverflow.com/a/11570414

[outer brook]

Try to remove the window.pack();

[manic bobcat]

didnt work and i got this error: ```Exception in thread "main" java.awt.IllegalComponentStateException: The frame is displayable.
at java.desktop/java.awt.Frame.setUndecorated(Frame.java:931)
at MyGame/main.Main.main(Main.java:30)

[steep fossil]

Detected code, here are some useful tools:

[WARNING] The code couldn't end properly...

Problematic source code:

Exception in thread "main" java.awt.IllegalComponentStateException: The frame is displayable.
    at java.desktop/java.awt.Frame.setUndecorated(Frame.java:931)
    at MyGame/main.Main.main(Main.java:30)```
Cause:
The code doesn't compile:
';' expected

## System out
[Nothing]

[manic bobcat]

didnt work sadly

[outer brook]

And call window.setVisible(true); just when you wanna show the Frame not right after the new JFrame()

I've just test it

[manic bobcat]

oh now it works tyssm

[outer brook]

import javax.swing.*;

public class TestSwing {
    public static void main(String... args) {
        
        JFrame window = new JFrame();
        //window.setVisible(true);  // <-------- Don't set it here!
        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        window.setResizable(false);
        window.setTitle("2D Adventure");

        //Just for test!
        JButton button = new JButton("Test");
        window.add(button);

        window.setExtendedState(window.MAXIMIZED_BOTH);

        //window.pack(); // <-------- Don't use pack!

        window.setLocationRelativeTo(null);        
        window.setVisible(true);
    }
}    

[steep fossil]

Detected code, here are some useful tools:

System out

[Nothing]