用三种不同的事件处理方式，实现点击按钮改变背景颜色和关闭窗口的功能。

package GUI;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import java.util.Random;
public class FrameTest1 extends Frame implements ActionListener{
Button button1;
Button button2;
Button button3;
public FrameTest1(){
this.setTitle("改变颜色");
this.setSize(400,300);
this.setLayout(new FlowLayout( ));
button1 = new Button("匿名");
button2 = new Button("内部类");
button3 = new Button("接口");
button1.addActionListener(new ActionListener() {
    @Override
    public void actionPerformed(ActionEvent actionEvent) {
        changeColor();
    }
});

buttonListener bl = new buttonListener();
button2.addActionListener(bl);

button3.addActionListener(this);

this.addWindowListener(new WindowListener() {
    @Override
    public void windowOpened(WindowEvent windowEvent) {

    }

    @Override
    public void windowClosing(WindowEvent windowEvent) {
        System.exit(0);
    }

    @Override
    public void windowClosed(WindowEvent windowEvent) {

    }

    @Override
    public void windowIconified(WindowEvent windowEvent) {

    }

    @Override
    public void windowDeiconified(WindowEvent windowEvent) {

    }

    @Override
    public void windowActivated(WindowEvent windowEvent) {

    }

    @Override
    public void windowDeactivated(WindowEvent windowEvent) {

    }
});

this.add(button1);
this.add(button2);
this.add(button3);

this.setResizable(false);
this.setVisible(true);

}
@Override
public void actionPerformed(ActionEvent actionEvent) {
changeColor();
}
class buttonListener implements ActionListener{
@Override
public void actionPerformed(ActionEvent actionEvent) {
    changeColor();
}

}
public void changeColor(){
Random random = new Random();
int r = random.nextInt(256);
int g = random.nextInt(256);
int b = random.nextInt(256);
Color c = new Color(r, g, b);
this.setBackground(c);
}
public static void main (String[] args){
new FrameTest1();
}

}