Java Threading - Three ways to create java threads

In programming, threading is a way of distributing our work. We can delegate a huge load of work in to several threads (i.e several processes). A thread will run as a separate operating system process which can run concurrently with other threads.

There are three ways of creating threads in java

1. Extend the thread class

Thread class has a run method and need override method with the code to run in a its own thread.

To execute code in a separate thread,

• Instantiate an object of class which is extended by Thread class (Runner)
• Invoke the start() method of Thread class.
• start() method will go to Thread class and look for the run method and invoke that in a separate thread.

2. Implement Runnable interface

• Implement Runnable interface in a class
• Pass object of that class to a constructor of Thread class.
• Invoke the start() method 

3. Instantiate a Thread object with a Runnable instance