Why does the ExecutorService interface not implement AutoCloseable?

Question

Failing to call shutdown() on a thread executor will result in a never terminating application.

Best practice to shut down the ExecutorService is this:

Answer 1

This is a mediocre workaround

ExecutorService service = Executors.newSingleThreadExecutor();
try (Closeable close = service::shutdown) {

}

Or, if the checked exception bothers you, you could write:

interface MyCloseable extends AutoCloseable {
    void close();
}

And then

ExecutorService service = Executors.newSingleThreadExecutor();
try (MyCloseable close = service::shutdown) {

}

Of course, you must never ever put anything between the assignment and the try statement, nor use the service local variable after the try statement.

Given the caveats, just use finally instead.