有没有大神帮忙解决一下

BiuBiui 2017-10-24 08:47:10

下面的代码为什么会出现异常
import java.awt.*;
import javax.swing.*;

public class yhdl extends JFrame{
JPanel mb1,mb2,mb3;
JButton an1,an2;
JLabel bq1,bq2;
JTextField wbk;
JPasswordField mmk;

public static void main(String[] args) {
yhdl a=new yhdl();
}

yhdl(){
mb1=new JPanel();
mb2=new JPanel();
mb3=new JPanel();
bq1=new JLabel("用户名");
bq2=new JLabel("密码");
an1=new JButton("登录");
an2=new JButton("取消");
wbk=new JTextField(10);
mmk=new JPasswordField(10);

this.setLayout(new GridLayout(3,2));

mb1.add(bq1); mb1.add(wbk);
mb2.add(bq2); mb2.add(mmk);
mb3.add(an1); mb3.add(an2);

this.add(mb1); this.add(mb2); this.add(mb3);

this.setTitle("用户登录");
this.setSize(230,150);
this.setLocation(500,500);
this.setResizable(false);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setVisible(true);

}

}

异常代码
Exception in thread "main" java.lang.StackOverflowError
at java.awt.Insets.<init>(Unknown Source)
at sun.awt.windows.WToolkit.getScreenInsets(Native Method)
at sun.awt.windows.WToolkit.getScreenInsets(Unknown Source)
at java.awt.Window.init(Unknown Source)
at java.awt.Window.<init>(Unknown Source)
at java.awt.Frame.<init>(Unknown Source)
at java.awt.Frame.<init>(Unknown Source)
at javax.swing.JFrame.<init>(Unknown Source)
at JPanel.<init>(JPanel.java:12)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)
at JPanel.<init>(JPanel.java:13)

...全文