Main thread terminates when main method exits

[Jeganathan Swaminathan]

I gone thru' the maha's discussion regarding thread. There it is clearly written that "MAIN THREAD IS ALIVE TILL ANY CHILD THREAD IS ALIVE" but from the program added below gives a different picture. So i expect some comments on this...

public class AfterAllThreadProgram extends Thread
{
static Thread t1;

public void run()
{
System.out.println("Thread Group Name is " + Thread.currentThread().getThreadGroup());
while(true)
{
System.out.println("Child Thread " + Thread.currentThread().getName());
System.out.println(t1.isAlive());//Prints first true indicating main is alive. This will
//continue atleast 1 sec. After that it prints false
//This means that main thread is dead.
System.out.println("Total Threads  " + Thread.currentThread().activeCount());
//Here the activecount always prints 2 Why??? It is suppose to be 1 as per my knowledge

}
}

public static void main(String args[]) throws InterruptedException
{
System.out.println(Thread.currentThread().getName()+ " is the Main Thread & started executing");
System.out.println("Thread Group Name is " + Thread.currentThread().getThreadGroup());

System.out.println("Total Threads in this ThreadGroup is " + Thread.currentThread().activeCount());
//Here it is printing 1 and it is correct since only main thread is alive

t1 = Thread.currentThread();

Thread t = new AfterAllThreadProgram();
System.out.println("Total Threads in this ThreadGroup is " + Thread.currentThread().activeCount());
//Here it is printing 2  even before starting child thread, why???
//my surprise is whether child thread is active even before starting it.

t.start();

sleep(1000);

System.out.println("Main Method terminated");
}
}

------------------
S.Jeganathan MCA
Software Engg.
PSI Data Systems Ltd.,
Bangalore.
[e-mail]

[Randall Twede]

it is because you created a new thread at this line:
t1 = Thread.currentThread();
the method currentThread() returned a Thread which you assigned to t1. now t1 points at the same Thread the JVM is running(which is executing main at the moment).

[Randall Twede]

i guess???