Java JScrollPane: Creates a QQ friend chat window and a jscrollpane window

Java JScrollPane: Creates a QQ friend chat window and a jscrollpane window

Program code:

package com.os.frame;import java.awt.BorderLayout;import java.awt.FlowLayout;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import javax.swing.ImageIcon;import javax.swing.JButton;import javax.swing.JComboBox;import javax.swing.JFrame;import javax.swing.JPanel;import javax.swing.JScrollPane;import javax.swing.JTextArea;import javax.swing.JTextField;/** *  * @author RenHongWei */public class MainFrame extends JFrame {    public static void main(String[] args) {        new MainFrame("QQ");    }    JPanel jp = null;    JTextArea jta = null;    JTextField jtf = null;    JScrollPane jsp = null;    JComboBox jcb = null;    JButton jb = null;    public MainFrame(String title) {        super(title);        initComponent();        initFrame();        initLayout();    }    private void initLayout() {        this.setLayout(new BorderLayout());        this.add(jsp);        this.add(jp, BorderLayout.SOUTH);    }    private void initFrame() {        this.setSize(500, 300);        this.setLocation(200, 200);        this.setIconImage(new ImageIcon("images/Penguins.jpg").getImage());        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        this.setVisible(true);    }    private void initComponent() {        jta = new JTextArea();        jsp = new JScrollPane(jta);        jp = new JPanel();        String[] chatter = { "Boy", "Lady" };        jcb = new JComboBox(chatter);        jtf = new JTextField(10);        jb = new JButton("Send");        jp.add(jcb);        jp.add(jtf);        jp.add(jb);    }}

Debugging interface: