I have a thread that runs perfectly fine every one second. But when I try to start or stop the thread with buttons, it doesn't work. What am I doing wrong? Here is the code:

			

			

			...
			

			volatile Thread runner;
			

			...
			

			

			//Start the thread
			

			public void start()
			

			{
			

			runner = new Thread(this);
			

			runner.start();
			

			}
			

			

			//Stop the thread
			

			public void stop()
			

			{
			

			runner = null;
			

			System.out.println("Thread has been stopped!");
			

			}
			

			

			//Run the thread once every second
			

			public void run()
			

			{
			

			Thread thisThread = Thread.currentThread();
			

			

			//while(runner == thisThread)
			

			while(stopButton.isEnabled())
			

			{
			

			//halt the thread for 1000 ms here
			

			try { runner.sleep(1000); }
			

			catch(InterruptedException ie)
			

			{ System.err.println("Thread Interrupted!"); }
			

			

			//process to be repeated here
			

			sendReq();
			

			TP.printOutput(i, ibuf, num_regs);
			

			GP.setAllParams(i, ibuf, num_regs);
			

			}
			

			}
			

			...
			

			

			public void actionPerformed(ActionEvent ae)
			

			{
			

			String command = ae.getActionCommand();
			

			

			if(command == START)
			

			{
			

			start();
			

			startButton.setEnabled(false);
			

			stopButton.setEnabled(true);
			

			}
			

			else //if the command is STOP
			

			{
			

			stop();
			

			stopButton.setEnabled(false);
			

			startButton.setEnabled(true);
			

			}
			

			}