JAVA GUI怎么改呀，这是什么，我照着学的都不行

package GUIstudy;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class Testest1 {
       public static void main(String[] args) {
           new MyFrame();
       }
}
class MyFrame extends Frame{
    public void MyFrame() {
        TextField textfield = new TextField();
        add(textfield);
        
        //监听文本框输入
        MyActionListener2 myActionListener = new MyActionListener2();
        textfield.addActionListener(myActionListener);
        
        textfield.setEchoChar('*');
        pack();
        setVisible(true);
    }
}
class MyActionListener2 implements ActionListener{

    @Override
    public void actionPerformed(ActionEvent e) {
        // TODO Auto-generated method stub
        TextField field =(TextField)e.getSource();        //获得资源
        System.out.println(field.getText());
        field.setText("");
    }
    
}

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这怎么回事呀

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