JApplet不使用图标或图像

Question

我正在开发一个新的Japplet，我的问题是，当我在eclipse中测试它时，它可以工作但是当我尝试在浏览器中测试它时，它会产生问题!!

package com.pack;

import javax.swing.JApplet;
import javax.swing.GroupLayout;
import javax.swing.GroupLayout.Alignment;
import javax.swing.JPanel;
import java.awt.SystemColor;
import javax.swing.JButton;
import javax.swing.LayoutStyle.ComponentPlacement;
import javax.swing.ImageIcon;

public class Essai extends JApplet {
private JPanel panel;
private JButton button;
private JButton button_1;

public Essai() {
    panel = new JPanel();
    panel.setBackground(SystemColor.inactiveCaption);

    button = new JButton("");
    button.setIcon(new ImageIcon(Essai.class.getResource("/com/pack/circle-check.png")));

    button_1 = new JButton("");
    button_1.setIcon(new ImageIcon(Essai.class.getResource("/com/pack/circle-delete.png")));
    GroupLayout groupLayout = new GroupLayout(getContentPane());
    groupLayout.setHorizontalGroup(
        groupLayout.createParallelGroup(Alignment.LEADING)
            .addGroup(groupLayout.createSequentialGroup()
                .addGap(21)
                .addComponent(button, GroupLayout.PREFERRED_SIZE, 58, GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(ComponentPlacement.UNRELATED)
                .addComponent(button_1, GroupLayout.PREFERRED_SIZE, 58, GroupLayout.PREFERRED_SIZE)
                .addContainerGap(303, Short.MAX_VALUE))
            .addGroup(Alignment.TRAILING, groupLayout.createSequentialGroup()
                .addContainerGap(GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addComponent(panel, GroupLayout.PREFERRED_SIZE, 431, GroupLayout.PREFERRED_SIZE)
                .addContainerGap())
    );
    groupLayout.setVerticalGroup(
        groupLayout.createParallelGroup(Alignment.LEADING)
            .addGroup(Alignment.TRAILING, groupLayout.createSequentialGroup()
                .addContainerGap(GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addGroup(groupLayout.createParallelGroup(Alignment.LEADING)
                    .addComponent(button, GroupLayout.PREFERRED_SIZE, 55, GroupLayout.PREFERRED_SIZE)
                    .addComponent(button_1, GroupLayout.PREFERRED_SIZE, 55, GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(ComponentPlacement.RELATED)
                .addComponent(panel, GroupLayout.PREFERRED_SIZE, 221, GroupLayout.PREFERRED_SIZE)
                .addGap(53))
    );
    getContentPane().setLayout(groupLayout);
}
}

我的小程序未在浏览器中显示。