Java.lang.Thread.activeCount() Method

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Description

The java.lang.Thread.activeCount() method returns the number of active threads in the current thread's thread group.

Declaration

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

public static int activeCount()

Parameters

NA

Return Value

This method returns the number of active threads in the current thread's thread group.

Exception

NA

Example

The following example shows the usage of java.lang.Thread.activeCount() method.

package com.tutorialspoint;

import java.lang.*;

public class ThreadDemo {

   public static void main(String[] args) {

      Thread t = Thread.currentThread();
      t.setName("Admin Thread");
      
      // set thread priority to 1
      t.setPriority(1);
     
      // prints the current thread
      System.out.println("Thread = " + t);

      int count = Thread.activeCount();
      System.out.println("currently active threads = " + count);
    
      Thread th[] = new Thread[count];
      // returns the number of threads put into the array 
      Thread.enumerate(th);
    
      // prints active threads
      for (int i = 0; i < count; i++) {
         System.out.println(i + ": " + th[i]);
      }
   }
} 

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

Thread = Thread[Admin Thread,1,main]
currently active threads = 1
0: Thread[Admin Thread,1,main]