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What it looks like

java.lang.InterruptedException: sleep interrupted

Extends Exception in java.lang.

What it means

Interruption is Java's cooperative way to ask a thread to stop. Blocking methods such as Thread.sleep, Object.wait, BlockingQueue.take and Future.get throw InterruptedException when the thread's interrupt flag is set, and they clear the flag when they throw. Swallowing the exception silently breaks shutdown and cancellation. The correct response is to stop what you are doing or to restore the flag.

Common causes

• An executor shutdown (shutdownNow), a timeout, or a cancel on a Future.
• The application is stopping and the container sends signals to worker threads.
• Another thread called thread.interrupt() to cancel work.
• A framework cancelling a task that exceeded its time limit.

How to fix it

1. Either propagate the exception or call Thread.currentThread().interrupt() before returning, so callers see the flag.
2. Never catch it and ignore it with an empty block.
3. Make long loops check Thread.interrupted() or isInterrupted() and exit cleanly.
4. Close resources in finally or try-with-resources so an interrupt does not leak them.

Broken and fixed

try { Thread.sleep(1000); } catch (InterruptedException e) { /* ignored */ }

try { Thread.sleep(1000); }
catch (InterruptedException e) {
    Thread.currentThread().interrupt(); // keep the signal
    return;
}

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In Spring and enterprise code

In Spring, scheduled and async tasks are interrupted on application shutdown. Handling interruption properly makes graceful shutdown (server.shutdown=graceful) work.

Debug it faster

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