Java method references while exception handling

Question

I have one method which throws checked exception:

private void testCacheExpiration() throws InterruptedException

I am trying to create a generic wrapper that will handle the exception gracefully.

private Runnable handleNonTestException(Runnable r) {
    return () -> {
        try {
            r.run();
        } catch (Exception e) {
            logger.error(NON_TEST_EXCEPTION_MSG, e);
            errors.add(new Error(e.getMessage(), NON_TEST_EXCEPTION_MSG));
        }
    };
}

Now I am using handleNonTestException(this::testCacheExpiration) which gives me compile time error unhandled exception type: InterruptedException . What may I be missing?

Maybe, you want to use a [`Callable`](https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/Callable.html)? — Seelenvirtuose, Mar 15 '18 at 16:51
You're providing `this::testCacheExpiration` as an implementation of the functional interface `Runnable`'s `run` method, which is not declared to throw an `InterruptedException`. — Sotirios Delimanolis, Mar 15 '18 at 16:52
The body of `handleNonTestException` does not make any difference here. — Sotirios Delimanolis, Mar 15 '18 at 16:52

Sagar · Accepted Answer · 2018-03-15T17:09:09.620

My testCacheExpiration method signature doesn't conform to the run method's signature in runnable interface (which doesn't throw any exception)

Following changes solved it:

@FunctionalInterface
private interface ThrowingRunnable <E extends Exception> {
    void run() throws Exception;
}

private Runnable handleNonTestException(ThrowingRunnable<? extends Exception> r) {
    return () -> {
        try {
            r.run();
        } catch (Exception e) {
            logger.error(NON_TEST_EXCEPTION_MSG, e);
            errors.add(new Error(e.getMessage(), NON_TEST_EXCEPTION_MSG));
        }
    };
}`

What’s the point of this type parameter you are not using? — Holger, Mar 16 '18 at 09:03

Java method references while exception handling

1 Answers1