Java命令执行失败

嘿，如果有人能找出为什么我的代码不起作用，那就太好了。每次我尝试以文件或项目的形式运行时，都会失败。我真的不知道该怎么做来尝试和修复这个问题，我是新的，所以如果这是一些基本的，我忽略了对不起。我正在运行netbeans 11.2，以防出现问题

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package com.gameclock;

import javax.swing.*;
import javax.swing.border.*;
import javax.swing.ImageIcon;
import javax.accessibility.*;

import java.awt.*;
import java.awt.event.*;
/**
 *
 * @author jacobk
 */
public class GameClock001 extends JFrame {

    private final JLayeredPane layeredpane;
    private JLabel background;

    private JLabel monthdot;
    private JLabel daydot;
    private JLabel hourdot;
    private JLabel mindot;
    private JLabel ampmdot;

    private JLabel monthbuttons;
    private JLabel daybuttons;
    private JLabel hourbuttons;
    private JLabel minbuttons;
    private JLabel ampmam;
    private JLabel ampmpm;

    private JButton monthup;
    private JButton monthdown;
    private JButton dayup;
    private JButton daydown;
    private JButton hourup;
    private JButton hourdown;
    private JButton minup;
    private JButton mindown;
    private JButton ampm;


    public GameClock001() {

        super("Game Clock");
        setSize(900, 603);
        setLookAndFeel();
        FlowLayout flo = new FlowLayout();
        setLayout(flo);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        ImageIcon Background = new ImageIcon("GameClockSmol.jpeg", "GameClockIMG");
        ImageIcon up = new ImageIcon("Up.jpeg", "Button Up");
        ImageIcon down = new ImageIcon("Down.jpeg", "Button Down");
        ImageIcon dot = new ImageIcon("dot_png29.png", "Dot");
        ImageIcon swap = new ImageIcon("switch.png", "Switch");
        layeredpane = new JLayeredPane();
        layeredpane.setPreferredSize(new Dimension(900, 563));

        int monthx = (0);
        int monthy = (0);
        int dayx = (0);
        int dayy = (0);
        int hourx = (0);
        int houry = (0);
        int minx = (0);
        int miny = (0);

        background.setIcon(Background);
        background.setBounds(0, 0, Background.getIconWidth(), Background.getIconHeight());
        monthdot.setIcon(dot);
        monthdot.setBounds(monthx, monthy, dot.getIconWidth(), dot.getIconHeight());
        daydot.setIcon(dot);
        daydot.setBounds(dayx, dayy, dot.getIconWidth(), dot.getIconHeight());
        hourdot.setIcon(dot);
        hourdot.setBounds(hourx, houry, dot.getIconWidth(), dot.getIconHeight());
        mindot.setIcon(dot);
        mindot.setBounds(minx, miny, dot.getIconWidth(), dot.getIconHeight());
        ampmdot.setIcon(dot);


        monthbuttons.setText("Month");
        daybuttons.setText("Day");
        hourbuttons.setText("Hour");
        minbuttons.setText("Minute");
        ampmam.setText("AM");
        ampmpm.setText("PM");



        monthup.setIcon(up);
        monthdown.setIcon(down);
        dayup.setIcon(up);
        daydown.setIcon(down);
        hourup.setIcon(up);
        hourdown.setIcon(down);
        minup.setIcon(up);
        mindown.setIcon(down);
        ampm.setIcon(swap);


    layeredpane.add(background, new Integer(3));

    layeredpane.add(monthdot, new Integer(1));
    layeredpane.add(daydot, new Integer(1));
    layeredpane.add(hourdot, new Integer(1));
    layeredpane.add(mindot, new Integer(1));
    layeredpane.add(ampmdot, new Integer(1));

    add(monthbuttons);
    add(daybuttons);
    add(hourbuttons);
    add(minbuttons);
    add(ampmam);
    add(ampmpm);

    add(monthup);
    add(monthdown);
    add(dayup);
    add(daydown);
    add(hourup);
    add(hourdown);
    add(minup);
    add(mindown);
    add(ampm);
    add(layeredpane);   


    }
    private void setLookAndFeel() {
        try {
            UIManager.setLookAndFeel(
            "com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
        } catch (Exception exc) {
            // ignore error     
        }
    }
    public static void main(String[] arguments) {
        GameClock001 frame = new GameClock001();
    }
}

---

我立即注意到的两件事是，您正在

main

线程上执行所有操作（该线程将立即终止），并且您从未将帧设置为可见。将

main（）

方法更改为

public static void main(String[] arguments) {
    SwingUtilities.invokeLater(new Runnable() {
        public void run() {
            GameClock001 frame = new GameClock001();
            frame.setVisible(true);
        }
    });
}

---

那么，它怎么会失败呢？我注意到你从来没有设置你的框架可见。你在

main

线程上执行所有操作。例如，

monthup

从未创建过，因此

monthup.setIcon

很可能失败。代码中也有更多这种故障类型的示例。您需要执行类似于

monthup=newjbutton（“单击”）首先。如果你能解释你更改了什么以及为什么更改，你的答案会更好，而不是仅仅转储大约一百行代码，并期望读者直观地识别你更改了什么。嘿，我试过了，它构建正确，但没有保持打开状态或向我显示窗口，所以现在我更困惑了。
/**
 * 
 */
private static final long serialVersionUID = 1L;
private final JLayeredPane layeredpane;
private JLabel background = new JLabel();

private JLabel monthdot = new JLabel();
private JLabel daydot = new JLabel();
private JLabel hourdot = new JLabel();
private JLabel mindot = new JLabel();
private JLabel ampmdot = new JLabel();

private JLabel monthbuttons = new JLabel();
private JLabel daybuttons = new JLabel();
private JLabel hourbuttons = new JLabel();
private JLabel minbuttons = new JLabel();
private JLabel ampmam = new JLabel();
private JLabel ampmpm = new JLabel();

private JButton monthup = new JButton();
private JButton monthdown = new JButton();
private JButton dayup = new JButton();
private JButton daydown = new JButton();
private JButton hourup = new JButton();
private JButton hourdown = new JButton();
private JButton minup = new JButton();
private JButton mindown = new JButton();
private JButton ampm = new JButton();


public GameClock001() {

    super("Game Clock");
    setSize(900, 603);
    setLookAndFeel();
    FlowLayout flo = new FlowLayout();
    setLayout(flo);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    ImageIcon Background = new ImageIcon();
    ImageIcon up = new ImageIcon("download.png", "Button Up");
    ImageIcon down = new ImageIcon("download.png", "Button Down");
    ImageIcon dot = new ImageIcon("download.png", "Dot");
    ImageIcon swap = new ImageIcon("download.png", "Switch");
    layeredpane = new JLayeredPane();
    layeredpane.setPreferredSize(new Dimension(900, 563));

    int monthx = (0);
    int monthy = (0);
    int dayx = (0);
    int dayy = (0);
    int hourx = (0);
    int houry = (0);
    int minx = (0);
    int miny = (0);

    background.setIcon(Background);
    background.setBounds(0, 0, Background.getIconWidth(), Background.getIconHeight());
    monthdot.setIcon(dot);
    monthdot.setBounds(monthx, monthy, dot.getIconWidth(), dot.getIconHeight());
    daydot.setIcon(dot);
    daydot.setBounds(dayx, dayy, dot.getIconWidth(), dot.getIconHeight());
    hourdot.setIcon(dot);
    hourdot.setBounds(hourx, houry, dot.getIconWidth(), dot.getIconHeight());
    mindot.setIcon(dot);
    mindot.setBounds(minx, miny, dot.getIconWidth(), dot.getIconHeight());
    ampmdot.setIcon(dot);


    monthbuttons.setText("Month");
    daybuttons.setText("Day");
    hourbuttons.setText("Hour");
    minbuttons.setText("Minute");
    ampmam.setText("AM");
    ampmpm.setText("PM");



    monthup.setIcon(up);
    monthdown.setIcon(down);
    dayup.setIcon(up);
    daydown.setIcon(down);
    hourup.setIcon(up);
    hourdown.setIcon(down);
    minup.setIcon(up);
    mindown.setIcon(down);
    ampm.setIcon(swap);


layeredpane.add(background, new Integer(3));

layeredpane.add(monthdot, new Integer(1));
layeredpane.add(daydot, new Integer(1));
layeredpane.add(hourdot, new Integer(1));
layeredpane.add(mindot, new Integer(1));
layeredpane.add(ampmdot, new Integer(1));

add(monthbuttons);
add(daybuttons);
add(hourbuttons);
add(minbuttons);
add(ampmam);
add(ampmpm);

add(monthup);
add(monthdown);
add(dayup);
add(daydown);
add(hourup);
add(hourdown);
add(minup);
add(mindown);
add(ampm);
add(layeredpane);   


}
private void setLookAndFeel() {
    try {
        UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
    } catch (Exception exc) {
        exc.printStackTrace();   
    }
}
public static void main(String[] arguments) {
    GameClock001 frame = new GameClock001();
    frame.setVisible(true);
}