Question

I have created a GUI for starting a Thread which does something very simple. However, the child thread never starts.

The child thread, if started, will give some output; I don’t get any output though. What am I missing?

Here’s the Code:

1. The GUI class:

   import java.awt.FlowLayout;
   import java.awt.event.ActionEvent;
   import java.awt.event.ActionListener;
   import javax.swing.JButton;
   import javax.swing.JFrame;
   
   
   public class gui {
       public static void main(String [] args) {           
           //final standalone s = new standalone();
           final try2 t= new try2();
   
           JFrame win = new JFrame();
           win.setLayout(new FlowLayout());
   
           JButton start = new JButton("Start");
           JButton stop = new JButton("Stop");
   
           start.addActionListener(new ActionListener() {
   
               @Override
               public void actionPerformed(ActionEvent e) {
                   // TODO Auto-generated method stub
                   t.t.start();
                   System.out.println("M on!");
                   try{
                   Thread.currentThread().sleep(10000);
                   }catch(Exception e1)
                   {
                       e1.printStackTrace();
                   }
                   System.out.println("M off!");
                   if(t.t.isInterrupted())
                       System.out.println("Stopped");
               }
           });         
   
           win.add(start);
           win.add(stop);
   
           win.setVisible(true);
       }
   }
   

2. And here is the Child Thread

   public class try2 implements Runnable {
       public Thread t;
       int i;
   
       try2() {
           t=new Thread();             
       }
   
       public void run() {
           System.out.println(++i);
       }
   }
   

Answer 1

Make your class try2 extends Thread (and remove the implements Runnable)., then simply call start() on your try2 instance.