Why invoke Thread.currentThread.interrupt() in a catch InterruptException block?

java, multithreading

Solution

This is done to keep state.

When you catch the `InterruptedException` and swallow it, you essentially prevent any higher-level methods/thread groups from noticing the interrupt. Which may cause problems.

By calling `Thread.currentThread().interrupt()`, you set the interrupt flag of the thread, so higher-level interrupt handlers will notice it and can handle it appropriately.

Java Concurrency in Practice discusses this in more detail in Chapter 7.1.3: Responding to Interruption. Its rule is:

Only code that implements a thread's interruption policy may swallow an interruption request. General-purpose task and library code should never swallow interruption requests.

Problem

Original source