java - 小程序未在我的班级中初始化

Question

我有一些我正在尝试运行的代码，但我不断收到“applet not initialized”的错误消息，我无法确定它为什么不起作用。

import javax.swing.*;
import java.util.*;

public class Assignment6 extends JApplet
{
    private int APPLET_WIDTH = 500, APPLET_HEIGHT = 200;

    private JTabbedPane tPane;
    private CreatePanel createPanel;
    private TransferPanel transferPanel;
    private Vector accountList;

    //The method init initializes the Applet with a Pane with two tabs
    public void init()
    {


        //list of accounts to be used in every panel
        accountList = new Vector();

        //register panel uses the list of accounts
        transferPanel = new TransferPanel(accountList);

        createPanel = new CreatePanel(accountList, transferPanel);

        //create a tabbed pane with two tabs
        tPane = new JTabbedPane();
        tPane.addTab("Account creation", createPanel);
        tPane.addTab("Account transfer", transferPanel);

        getContentPane().add(tPane);
        setSize (APPLET_WIDTH, APPLET_HEIGHT); //set Applet size
    }
}