Prevent a Thread : yield()

• yield() method causes "to pause current executing Thread for giving the chance of remaining waiting Threads of same priority".

• If all waiting Threads have the low priority or if there is no waiting Threads then the same Thread will be continued its execution.

• If several waiting Threads with same priority available then we can't expect exact which Thread will get chance for execution.

• The Thread which is yielded when it get chance once again for execution is depends on mercy of the Thread scheduler.

• public static native void yield();

 Lifecycle Diagram: Below is the life cycle diagram of a Thread using yield()

 

class MyThread extends Thread {       public void run()       {                   for(int i=0;i<5;i++)                   {                               Thread.yield(); System.out.println("child thread");                   }       } } class ThreadYieldDemo {       public static void main(String[] args)       {                   MyThread t=new MyThread(); t.start();                   for(int i=0;i<5;i++)                   {                               System.out.println("main thread");                   }       } }

Output: 

main thread

main thread

main thread

main thread

main thread

child thread

child thread

child thread

child thread

child thread

• In the above program child Thread always calling yield() method and hence main Thread will get the chance more number of times for execution.

• Hence the chance of completing the main Thread first is high.

Note : Some operating systems may not provide proper support for yield() method.

Multithreading Agenda

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