代码出错了

[Sodino]

照着Java核心技术卷敲的代码,不明白为什么出错了.

运行后eclipse提示:
java.lang.Error: Do not use NotHelloWorldFrame.add() use NotHelloWorldFrame.getContentPane().add() instead
at javax.swing.JFrame.createRootPaneException(Unknown Source)
at javax.swing.JFrame.addImpl(Unknown Source)
at java.awt.Container.add(Unknown Source)
at NotHelloWorldFrame.<init>(NotHelloWorld.java:20)
at NotHelloWorld.main(NotHelloWorld.java:6)

import java.awt.*;
import javax.swing.*;

public class NotHelloWorld {
	public static void main(String[] args) {
		NotHelloWorldFrame nhwf = new NotHelloWorldFrame();
		nhwf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		nhwf.setVisible(true);
	}
}

class NotHelloWorldFrame extends JFrame {
	public static final int DEFAULT_WIDTH = 300;
	public static final int DEFAULT_HEIGHT = 200;

	public NotHelloWorldFrame() {
		setTitle("NotHelloWorld");
		setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
		add(new NotHelloWorldPanel());
	}
}

class NotHelloWorldPanel extends JPanel {
	public void paintComponent(Graphics g) {
		super.paintComponent(g);
		g.drawString("NotHelloWorld", 50, 50);
	}
}

[ty_tarena_pger]

	
public NotHelloWorldFrame() {
   setTitle("NotHelloWorld");
   setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
    getContentPane().add(new NotHelloWorldPanel());//add(new NotHelloWorldPanel());换成前面的
    //我的编译器上上面两种都可以运行
   
}

[ty_tarena_pger]

可能是你的版本问题,我5.0的

[不善^]

我运行了 没报错啊 弹出一个窗口的啊

[frankwoods123]

升级jdk版本到最新版

[「已注销」]

java -version 查看你的jdk 版本