Is there any mistake in this Thread code.

[krishna Karthikk]

Hi everybody, I am Krishna, I have written this code on Threads, I don't know why this is not working, it is not giving a compile time error or run time error. The run() is not being executed.

The code is

class NewThread implements Runnable
{
	Thread t=null;
	NewThread()
	{
		t=new Thread();
		t.start();
	}
	public void run()
	{
		try
		{
			for(int i=0;i<10;i++)
			{
				System.out.print(i);
				Thread.sleep(500);
			}
		}catch(Exception e){}
	}
}
class ThreadDemo
{
	public static void main(String s[])
	{
		new NewThread();
		try
		{
			for(int i=0;i<10;i++)
			{
				System.out.print(i);
				Thread.sleep(500);
			}
		}catch(Exception e){}
	}
}

Can anybody tell me what is wrong in this code. Thanks in advance. Have a nice day.

[Ulf Dittmer]

You aren't starting NewThread, you're starting some other thread that does nothing. Also, remove lines 3 to 8 from the code; they're not needed.

[krishna Karthikk]

Hi Dittmer, I removed that lines and executed it again, but the run method is not being executed.
The output is 0123456789 with a delay of 500 milliseconds

[Christian Dillinger]

public class StupidRunnable implements Runnable {

	@Override
	public void run() {
		for (int i = 0; i < 10; i++) {
			System.out.print(i);
			try {
				Thread.sleep(500);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}

	public static void main(String s[]) {
		new Thread(new StupidRunnable()).start();
		try {
			for (int i = 0; i < 10; i++) {
				System.out.print(i);
				Thread.sleep(500);
			}
		} catch (Exception e) {
		}
	}
}

You didn't read that part of Ulf's answer:

Ulf Dittmer wrote:You aren't starting NewThread

[Jim Hoglund]

You must start() your anonymous NewThread object.
How are you learning about threads?

Jim ... ...

[Christian Dillinger]

Jim Hoglund wrote:You must start() your anonymous NewThread object.

NewThread is a Runnable so he cannot call start().

[krishna Karthikk]

The code is now executing, I missed this one

NewThread()  
    {  
        t=new Thread(this);  //forgot to mention "this"
        t.start();  
    }  

[Christian Dillinger]

That's a very uncommon use of threads. I'd recommend using the normal way... If you come to the chapter "executors" you'll understand why you should...

[Jim Hoglund]

Good point. Is it working now? If you wish, you
can post the entire program again for review.

Jim ... ...

[krishna Karthikk]

This is the correct code. Let em know it is efficient or not.

class NewThread implements Runnable
{
	public NewThread()
	{
		Thread t=new Thread(this);
		t.start();
	}
	public void run()
	{
		try
		{
			for(int i=0;i<10;i++)
			{
				System.out.print(i);
				Thread.sleep(500);
			}
		}catch(Exception e){}
	}
}
class ThreadDemo
{
	public static void main(String s[])
	{
		new NewThread();
		try
		{
			for(int i=0;i<10;i++)
			{
				System.out.print(i);
				Thread.sleep(500);
			}
		}catch(Exception e){}
	}
}

[Paul Clapham]

krishna anusha wrote:This is the correct code. Let em know it is efficient or not.

It would run much faster if you didn't have Thread.sleep all over the place. Or was that not what you meant by "efficient"?

[krishna Karthikk]

Hi Paul, thanks for the suggestion, I didn't get you, is the Thread.sleep() not efficient. Can you tell me how?

Thank you in advance.