编写程序，包含3个标签，其背景分别为红、黄、蓝3色

import java.awt.*;import java.awt.event.*;public class LabelRYB extends Frame {private Label label1 = new Label("RedLabel");private Label label2 = new Label("YellowLabel");private Label label3 = new Label("BlueLabel");public class WindowCloser extends WindowAdapter{public void windowClosing(WindowEvent we){System.exit(0);}}public LabelRYB(){super("TestLabel window");setLayout(new FlowLayout());add(label1); label1.setBackground(Color.red);add(label2); label2.setBackground(Color.yellow);add(label3); label3.setBackground(Color.blue);addWindowListener(new WindowCloser());pack();setVisible(true);}public static void main(String[] args){LabelRYB ryb = new LabelRYB();}}