A thread is basically a stream of instruction executed sequentially. It is used to implement multitasking in a program. A program can have multiple threads. Threads are used to do multiple things at the same time. Threads are basically used to perform complicated tasks in the background without affecting the main program.
There are two methods to display all running threads in Java
1. Using The ThreadGroup Object
Java provides us a way to group multiple threads in a single object. In Java, a group of threads ie thread groups is being implemented by ThreadGroup class, so here we will be using a ThreadGroup object to group all the threads currently running. After this, we will be using the activeCount() method of ThreadGroup to get the number of active threads, then we will use the enumerate(Thread list) method of the ThreadGroup which will copy the currently active threads in an array, and we will loop over the array to get the names of all the active threads.
2. Using getAllStackTrace() Method
The getAllStackTrace() method gives a stack trace of all the running threads. Then we make a set of the keys of that element because the method returns a map, and then we loop over all the elements of the set to print all the running threads.
Overriden Run Method Overriden Run Method Thread-0 Reference Handler Thread-1 Signal Dispatcher main Finalizer
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