Thread activeCount() method in Java

Thread’s activeCount() is a static method which returns a number of active threads. Internally it calls ThreadGroup’s activeCount() method.

Declaration – public static int activeCount()

Let’s see an example –

Output is – 1

In the above program by default, we have the main thread running that’s why the count is one.

Internal implementation.

Example 2 – In this example, we will create two thread and we will see what is count.

Output is –

Using Thread class thread created
Using Runnable interface thread created

Note – In the above example, we have created Active thread count may vary because before executing line 22 it may possible user-defined thread has been stopped.