Threads and synchronization

[ajay mv]

package com.home.scjp;

public class SimpleScheduling implements Runnable
{
   public void run()
   {
	   synchronized(this)
	   {
		   try
		   {
			   System.out.println("Inside" +" "+Thread.currentThread().getName());
			   this.wait();
			   System.out.println(Thread.currentThread().getName()+"came out of waiting state");
		   }
		   catch(Exception e)
		   {
		   
		   }
	   }
   }   

}

class Scheduling
{
	public static void main(String[] args)
	{
		try{
		SimpleScheduling ss=new SimpleScheduling();
		Thread t1=new Thread(ss);
		Thread t2=new Thread(ss);
		Thread t3=new Thread(ss);
		t1.start();
		t2.start();
		t3.start();
		ss.notifyAll();
		System.out.println("notified all waiting threads");
		}
		catch(Exception e)
		{
			System.out.println(e);
		}
	}
}

i am getting IllegalMonitorStateException Exception.

[Jeff Verdegan]

Hi, and welcome to the Ranch!

When posting code, if you UseCodeTags(←click), it will be easier to read, which will make it easier for people to help you. I've added the code tags to your original post.

As for your question, if you read the docs for that exception, it explains what causes it. I'm pretty sure it's also covered in the docs for wait(), notify(), and notifyAll(). In short, you can only call X.wait(), X.notify(), or X.notifyAll() if you're inside a synchronized (X) { ... } block, or an equivalent synchronized method. If you're getting that exception, it's because you're calling one of those methods on a object you're not synchronized on.

[ajay mv]

Thankyou Jeff