Question

Is a volatile required in the kill variable that controls the execution of the thread?

public class MyThread extends Thread{  

  private boolean kill = false;  

  public void killThread(){  
      kill = true;  
  }  

  @Override  
  public void run(){  
     while(!kill){  
                 //do stuff  
     }  
  }  

}  

For example if in some other part of the code (another thread) I do theThreadRef.killThread(); should I expect the thread to stop or is the result unpredictable due to not having declared kill as volatile? I am not sure on this since I update the kill via the killThread method.
Thanks

Answer 1

Yes, kill is a variable shared between threads and must be volatile. However, consider using Java’s native interruption mechanism, involving Thread.interrupt() and Thread.interrupted(), to achieve what you need. Then you won’t need to keep your own variable.