更改屏幕分辨率后，java JFrame始终处于顶部不工作

Question

问题1）我有一个JFrame，我希望它始终处于顶部，但在通过编程更改屏幕分辨率后，setAlwaysOnTop（）不会生效

问题2）为什么显示相同屏幕分辨率（高度、重量、速率、位深度）的3倍

import java.awt.Dimension;
import java.awt.DisplayMode;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;


@SuppressWarnings("serial")
public class DisplayModeChanger1 extends JFrame {

private static GraphicsDevice device;
private static JButton BtnChangeResolution = new JButton("Dummy Btn");
private static boolean isFullScreenSupported = false;
static JFrame f = new JFrame();
static int vcHight = 0;     
static int vcWeight = 0;
static int vcRate = 0;
static int vcBitDepth = 0;

public DisplayModeChanger1(final GraphicsDevice device) {
    DisplayModeChanger1.device = device;


}


public static void main(String[] args) {
    GraphicsEnvironment env = GraphicsEnvironment.getLocalGraphicsEnvironment();
    GraphicsDevice defaultScreen = env.getDefaultScreenDevice();
    DisplayModeChanger1 changer = new DisplayModeChanger1(defaultScreen);
    DisplayMode dm = null;

    GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
    GraphicsDevice display = ge.getDefaultScreenDevice();
    DisplayMode[] availableModes = display.getDisplayModes();

    for (DisplayMode DV : availableModes) {

        vcHight = DV.getWidth();
        vcWeight = DV.getHeight();
        vcRate = DV.getRefreshRate();
        vcBitDepth = DV.getBitDepth();  

        //change screen resolution if desired resolution found
        if(DV.getWidth() == 800 && DV.getHeight() == 600){
            vcHight = DV.getWidth();
            vcWeight = DV.getHeight();
            vcRate = DV.getRefreshRate();
            vcBitDepth = DV.getBitDepth(); 

            //Assigning Display Mode 
            dm = new DisplayMode(vcHight, vcWeight, vcBitDepth, vcRate);

            System.out.println(vcHight);
            System.out.println(vcWeight);
            System.out.println(vcRate);
            System.out.println(vcBitDepth);
            System.out.println("----------------------------------------------------------\n");

        }                                 
    }    

    isFullScreenSupported = device.isFullScreenSupported();       
    if (isFullScreenSupported) {
        f.setExtendedState(JFrame.MAXIMIZED_BOTH);
        f.setAlwaysOnTop(true);
        device.setFullScreenWindow(f);
        f.validate();
    } else {
        System.out.println("NO");
        f.pack();
        f.setVisible(true);
    }

    try {

         device.setDisplayMode(dm);
         f.setSize(new Dimension(dm.getWidth(), dm.getHeight()));  
         System.out.println("Screen height resolution was changed to [ " + dm.getHeight() + " ]");
         System.out.println("Screen width  resolution was changed to [ " +dm.getWidth() + " ]");
         f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         f.setResizable(false);
         f.add(BtnChangeResolution);
         //f.validate();
    } catch (Exception e2) {
        JOptionPane.showMessageDialog(null,  "ERROR--->" + e2);
    }      

   }
}