Write a Java program to create a group of a thread

The Java code demonstrates how to use the ThreadGroup class to group threads together and manage them as a single entity. The code creates a thread group named "MyThreadGroup" and assigns two threads, thread1 and thread2, to this thread group. It then starts both threads and performs operations on the thread group. In the ThreadGroupExample class:

A new thread group named "MyThreadGroup" is created using the constructor new ThreadGroup("MyThreadGroup").
Two threads, thread1 and thread2, are created and associated with the "MyThreadGroup" thread group using new Thread(threadGroup, new MyRunnable(), "Thread 1") and new Thread(threadGroup, new MyRunnable(), "Thread 2").
Both thread1 and thread2 are started using the start() method.
The code then prints the number of active threads in the thread group using threadGroup.activeCount().
It also prints the names of the threads currently in the thread group using the enumerate(Thread[] tarray) method.

The enumerate(Thread[] tarray) method copies the threads in the thread group into the provided array tarray. It returns the number of threads copied. The array threads is created with the size of the active thread count in the thread group using threadGroup.activeCount(). The loop then iterates over the threads array and prints the name of each thread.

Source Code

public class ThreadGroupExample
{
 
	public static void main(String[] args)
	{
		ThreadGroup threadGroup = new ThreadGroup("MyThreadGroup");
 
		Thread thread1 = new Thread(threadGroup, new MyRunnable(), "Thread 1");
		Thread thread2 = new Thread(threadGroup, new MyRunnable(), "Thread 2");
 
		thread1.start();
		thread2.start();
 
		// Print active thread count in the thread group
		System.out.println("Active Threads in Thread Group : " + threadGroup.activeCount());
 
		// Print details of threads in the thread group
		System.out.println("Threads in Thread Group :");
		Thread[] threads = new Thread[threadGroup.activeCount()];
		threadGroup.enumerate(threads);
		for (Thread thread : threads)
		{
			System.out.println(thread.getName());
		}
	}
 
	static class MyRunnable implements Runnable
	{
		public void run()
		{
			System.out.println(Thread.currentThread().getName() + " is Running.");
			try {
				Thread.sleep(2000); // Sleep for 2 seconds
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.println(Thread.currentThread().getName() + " has Completed.");
		}
	}
}

Output

Active Threads in Thread Group : 2
Threads in Thread Group :
Thread 1 is Running.
Thread 2 is Running.
Thread 1
Thread 2
Thread 1 has Completed.
Thread 2 has Completed.