I started recently learning how to use Jframe so I can make actual GUIs because no one wants an application that relies solely on cmd, so while making a basic demo app that uses a little bit of everything, I learned how to fullscreen using GraphicsDevice and GraphicsEnvironment and I also set the display mode to 2560 x 1440, 32 bit depth, and 60 fps. But for some reason, whenever the application is in fullscreen, it has these weird stutters and short fps drops after the window is open for around 1 to 2 seconds. I tried changing the resolution, framerate, and bit depth with display mode, but nothing changes unless I exit fullscreen. What do I do? (Sorry in advance, messy code that I was just playing around with. Not exactly a professional programmer, just a hobby thing)

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

public class Gui {

    public static void main(String[] args) {
        JFrame f = new JFrame("Demo Thingy");
        GraphicsEnvironment graphics = GraphicsEnvironment.getLocalGraphicsEnvironment();
        GraphicsDevice device = graphics.getDefaultScreenDevice();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        final JTextField tf = new JTextField();
        tf.setBounds(50, 50, 150, 20);
        JButton b = new JButton("Click to exit");
        JButton b2 = new JButton("Click here to fullscreen/exit fullscreen");
        b2.setBounds(600, 100, 250, 30);
        b2.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                if (device.getFullScreenWindow() == f) {
                    device.setFullScreenWindow(null);
                    f.setSize(1000, 1000);
                    f.setVisible(true);
                } else if (device.getFullScreenWindow() == null) {
                    device.setFullScreenWindow(f);
                    f.setVisible(true);
                }
            }
        });
        b.setBounds(50, 100, 250, 30);
        b.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                System.exit(0);
            }
        });
        f.add(b);
        f.add(b2);
        f.add(tf);
        f.setResizable(false);
        f.setUndecorated(true);
        device.setFullScreenWindow(f);
        device.setDisplayMode(new DisplayMode(2560, 1440, 16, 60));
        f.setVisible(true);
    }
}