How to properly stop the Thread in Java?

Question

I need a solution to properly stop the thread in Java.

I have IndexProcessorclass which implements the Runnable interface:

public class          


        

Answer 1

Simple answer: You can stop a thread INTERNALLY in one of two common ways:

• The run method hits a return subroutine.
• Run method finishes, and returns implicitly.

You can also stop threads EXTERNALLY:

• Call system.exit (this kills your entire process)
• Call the thread object's interrupt() method *
• See if the thread has an implemented method that sounds like it would work (like kill() or stop())

*: The expectation is that this is supposed to stop a thread. However, what the thread actually does when this happens is entirely up to what the developer wrote when they created the thread implementation.

A common pattern you see with run method implementations is a while(boolean){}, where the boolean is typically something named isRunning, it's a member variable of its thread class, it's volatile, and typically accessible by other threads by a setter method of sorts, e.g. kill() { isRunnable=false; }. These subroutines are nice because they allow the thread to release any resources it holds before terminating.