Write a Java program to check thread is alive or not

The Java code defines two classes: CheckThread and MyThread. The CheckThread class is the main class, and the MyThread class implements the Runnable interface to define the behavior of the thread.

In the CheckThread class, the main method creates a new thread t by passing an instance of MyThread to its constructor. The code then prints the status of the thread using the isAlive() method before and after starting the thread.

The isAlive() method is used to check if a thread is still alive or has terminated. It returns true if the thread has been started and has not yet completed (i.e., is still running) and false otherwise. Here's what happens step by step when you run this code:

A new thread t is created but not started yet.
The code prints "Thread isAlive : false" because the thread has not been started, and thus it is not yet alive.
The t.start() method is called to start the thread's execution.
The code immediately prints "Thread isAlive : true" because t has been started, but the run() method's execution might not have completed yet.
The run() method of the MyThread class prints "Thread is running." to the console.
The run() method completes, and the thread's execution finishes.
The code again prints "Thread isAlive : false" because the thread has completed its execution and is no longer alive.

Source Code

public class CheckThread
{
	public static void main(String[] args)
	{
		Thread t = new Thread(new MyThread());
 
		System.out.println("Thread isAlive : " + t.isAlive());
		t.start();
		System.out.println("Thread isAlive : " + t.isAlive());
	}
}
class MyThread implements Runnable
{
	public void run()
	{
		try
		{
			System.out.println("Thread is running.");
		} catch (Exception e)
		{
			System.out.println(e);
		}
	}
}

Output

Thread isAlive : false
Thread isAlive : true
Thread is running.