Java.lang.ThreadGroup.isDestroyed() Method

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Description

The java.lang.ThreadGroup.isDestroyed() method tests if this thread group has been destroyed.

Declaration

Following is the declaration for java.lang.ThreadGroup.isDestroyed() method

public boolean isDestroyed()

Parameters

NA

Return Value

This method returns true if this object is destroyed.

Exception

NA

Example

The following example shows the usage of java.lang.ThreadGroup.isDestroyed() method.

package com.tutorialspoint;

import java.lang.*;

public class ThreadGroupDemo implements Runnable {
   public static void main(String[] args) {
      ThreadGroupDemo tg = new ThreadGroupDemo();
      tg.func();
   }

   public void func() {
      try {     
         // create a parent ThreadGroup
         ThreadGroup pGroup = new ThreadGroup("Parent ThreadGroup");
    
         // create a child ThreadGroup for parent ThreadGroup
         ThreadGroup cGroup = new ThreadGroup(pGroup, "Child ThreadGroup");

         // create a thread
         Thread t1 = new Thread(pGroup, this);
         System.out.println("Starting " + t1.getName() + "...");
         t1.start();
            
         // create another thread
         Thread t2 = new Thread(cGroup, this);
         System.out.println("Starting " + t2.getName() + "...");
         t2.start();

         // block until the other threads finish
         t1.join();
         t2.join();

         try {
            // child group destroyed
            if (!cGroup.isDestroyed()) {
               cGroup.destroy();
            } else {
               System.out.println(cGroup.getName() + " destroyed");
            }
         } catch(IllegalThreadStateException ex) {
            System.out.println(cGroup.getName() + " is empty: " + ex.toString());
         }

         try {
            // parent group destroyed
            if (!pGroup.isDestroyed()) {
               pGroup.destroy();
            } else {
               System.out.println(pGroup.getName() + " destroyed");
            }
         } catch(IllegalThreadStateException ex) {
            System.out.println(pGroup.getName() + " is empty: " + ex.toString());
         }

      } catch (InterruptedException ex) {
         System.out.println(ex.toString());
      }
   }

   // implements run()
   public void run() {

      for(int i = 0;i < 1000;i++) {
         i++;
      }
      System.out.println(Thread.currentThread().getName() + " finished executing.");
   }
} 

Let us compile and run the above program, this will produce the following result −

Starting Thread-0...
Starting Thread-1...
Thread-0 finished executing.
Thread-1 finished executing.

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