What does java.lang.Thread.interrupt() do?

Thread.interrupt() method sets internal 'interrupt status' flag. Usually that flag is checked by Thread.interrupted() method.

By convention, any method that exists via InterruptedException have to clear interrupt status flag.

I want to add one or two things to the above answers.

1. One thing to remember is that, calling on the interrupt method does not always cause InterruptedException. So, the implementing code should periodically check for the interrupt status and take appropriate actions.

2. Thread.currentThread().isInterrupted() can also be used to check the interrupt status of a thread. Unlike the Thread.interrupted() method, it does not clear the interrupt status.