Java Thread isInterrupted() Method

Description

The Java Thread isInterrupted() method tests whether this thread has been interrupted. The interrupted status of the thread is unaffected by this method.

A thread interruption ignored because a thread was not alive at the time of the interrupt will be reflected by this method returning false.

Declaration

Following is the declaration for java.lang.Thread.isInterrupted() method

public boolean isInterrupted()

Parameters

NA

Return Value

This method returns true if this thread has been interrupted; false otherwise.

Exception

NA

Example: Checking if thread is interrupted

The following example shows the usage of Java Thread isInterrupted() method. In this program, we've created a thread class ThreadDemo by implementing Runnable interface. In constructor, a new thread is created using new Thread. Its name is printed using getName() and using start() method, thread is started. Using isInterrupted() method, we're checking if thread is not interrupted then interrupt the thread using interrupt() method. Thereafter we block the thread using join() method. In run() method, we added a sleep of 1 second in while(true) loop, which causes an InterruptedException.

In main method, we've created two threads of ThreadDemo.

package com.tutorialspoint;

public class ThreadDemo implements Runnable {

   Thread t;

   ThreadDemo() {

      t = new Thread(this);
      System.out.println("Executing " + t.getName());
      // this will call run() fucntion
      t.start();
        
      // tests whether this thread has been interrupted
      if (!t.isInterrupted()) {
         t.interrupt();
      }
      // block until other threads finish
      try {  
         t.join();
      } catch(InterruptedException e) {}
   }

   public void run() {
      try {       
         while (true) {
            Thread.sleep(1000);
         }
      } catch (InterruptedException e) {
         System.out.print(t.getName() + " interrupted:");
         System.out.println(e.toString());
      }
   }

   public static void main(String args[]) {
      new ThreadDemo();
      new ThreadDemo();
   }
} 

Output

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

Executing Thread-0
Thread-0 interrupted:java.lang.InterruptedException: sleep interrupted
Executing Thread-1
Thread-1 interrupted:java.lang.InterruptedException: sleep interrupted