Executing two threads simultaneously.

[Onra]

Hello,

I have two threads and I want to execute them simultaneously.

This is my code:

public final class MainClass {
	public static void main(String[] args){
		Thread a = new MyThread(doa);
		Thread b = new MyThread(dob);
		a.run();
		b.run();
	}
}

This, however, executes Thread a first and then after Thread a is finished it executes Thread b.

But I want to run them simultaneously. How do I do that?

[JosAH]

Hello,

I have two threads and I want to execute them simultaneously.

This is my code:

public final class MainClass {
	public static void main(String[] args){
		Thread a = new MyThread(doa);
		Thread b = new MyThread(dob);
		a.run();
		b.run();
	}
}

This, however, executes Thread a first and then after Thread a is finished it executes Thread b.

But I want to run them simultaneously. How do I do that?

Use the start() method of the Thread, not its run() method (it's all in the API documentation).

kind regards,

Jos

[Onra]

Ok, now a new question.

How can I make two threads run alternatively?

Thread A
Thread B
Thread A
Thread B
Thread A
Thread B

etc.

I want to do it with a control variable, but it doesn't work out.

[j2me64]

Ok, now a new question.

How can I make two threads run alternatively?

Thread A
Thread B
Thread A
Thread B
Thread A
Thread B

etc.

I want to do it with a control variable, but it doesn't work out.

put one thread to sleep for some millis inside your thread so that the other thread can be served.

[JosAH]

Ok, now a new question.

How can I make two threads run alternatively?

Thread A
Thread B
Thread A
Thread B
Thread A
Thread B

etc.

I want to do it with a control variable, but it doesn't work out.

If you want that there's no reason to run two threads; thread B has to wait until thread A has finished and vice versa. Better use a simple loop that runs both jobs alternately.

kind regards,

Jos

[j2me64]

But I want to run them simultaneously. How do I do that?

unless you have a mulicore-processor this is not really possible. the jvm switches between threads that fast that it looks like "simulaneously", but it isn't. and you can't force when a threads has to be started, the threads-scheduler decide when. nevertherless here is a bit of code that simulate something like you want.

public class MyThread extends Thread {

	public void run() {
		while (true) {
			try {
				System.out.println("Hallo, I'm thread " + this.getName());
				this.sleep(5);
			} catch (InterruptedException ex) {
				ex.printStackTrace();
			}
		}
	}

	public static void main(String[] args) {
		MyThread a = new MyThread();
		MyThread b = new MyThread();
		a.start();
		b.start();
	}

}

the principle is simple. after a thread has prompted "Hallo, I'm ..." it sleeps for 5 milliseconds so that the other thread can be started. watch out: the example has a endless while-loop.