Most developers work with threads at one point or another. It can be important to know which threads are active to accomplish a given task. The following API activeCount on the Thread class returns the count of the active threads in the current run time.

public class ActiveThreadsCount{   public static void main(String args[])   {      ActiveThreadsCount activeThreadsCount = new ActiveThreadsCount();      activeThreadsCount.countThreads();   }   private void countThreads()   {      //This can be invoked at a complex code segment and you cn determine the count      int threadsCount = java.lang.Thread.activeCount();       System.out.println("Count of active threads: " + threadsCount);   }}