multithreading - Java: Difference in usage between Thread.interrupted() and Thread.isInterrupted()?

Question

Java question: As far as I know, there are two ways to check inside a thread whether the thread received an interrupt signal, Thread.interrupted() and Thread.isInterrupted(), and the only difference between them is that the former resets the internal interrupted flag.

So far, I've always used Thread.isInterrupted() and never had any problems with it. Then again, most tutorials I've seen recommend using Thread.interrupted(). Is there any specific reason for that?

Answer 1

interrupted() is static and checks the current thread. isInterrupted() is an instance method which checks the Thread object that it is called on.

A common error is to call a static method on an instance.

Thread myThread = ...;
if (myThread.interrupted()) {} // WRONG! This might not be checking myThread.
if (myThread.isInterrupted()) {} // Right!

Another difference is that interrupted() also clears the status of the current thread. In other words, if you call it twice in a row and the thread is not interrupted between the two calls, the second call will return false even if the first call returned true.

The Javadocs tell you important things like this; use them often!