请问以下程序 导出后第一天能用 第二天就只能打开窗口，线程部分就不能用了，求教

Question

package project7;
import java.awt.*;
import java.util.*;
import java.awt.event.*;
import javax.swing.*;
public class Class1{
JButton jb;
JTextArea jta;
public static void main(String[] args) {

    JButton jb=new JButton("确定");
    JTextArea jta=new JTextArea();
    JFrame jf=new JFrame("窗口窗口");
    jf.add(jta,BorderLayout.CENTER);
    jb.setBounds(20,20,80,60);
    Class3 cl=new Class3();
    jb.addActionListener(cl);
    jf.add(jb,BorderLayout.SOUTH);
    jf.setBounds(50,50,320,560);
    jf.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
    jf.setVisible(true);

//@SuppressWarnings("unused")
//Class2 class2=new Class2();
}class Th extends Thread
{
String s=new String();
public void run(){
try{

            s=jta.getText();
            @SuppressWarnings("resource")
            Scanner sc=new Scanner(s);
            StringBuffer sb2=new StringBuffer("");
            while(sc.hasNext())
            {
                String s1=sc.nextLine();
                StringBuffer sb1=new StringBuffer(s1);              
                sb2=sb2.append(sb1);
            }
        s=sb2.toString();
        try{jta.setText(s);}
        catch(Exception e3)
        {
            System.out.println("wonoma");
        }
        }catch(Exception e2)
        {
            jta.setText("福线程本身："+e2.toString());
        }
        }
    }

}
class Class3 extends Class1 implements ActionListener{
public void actionPerformed(ActionEvent e)
{
//if(jta.getText()=="12345")
//{
if(e.getSource()==jb)
{try{Th th=new Th();
th.start();}
catch(Exception e1)
{
jta.setText("主程序执行副线程"+e1.toString());

}
}

}}

Answer 1

调试一下 看一下代码执行到那句话了，在卡住的地方找一下逻辑问题