Retry an action in Java
Java interview exercise on Exceptions & validation, difficulty 2 of 3. Solve it in the editor beside a worked example, or cold in Interview mode with the example hidden; the tests run the moment you do.
Write static <T> T retry(action, attempts) that calls the Supplier<T> up to attempts times and returns its first successful result. Only RuntimeException counts as a failure to retry; when the last attempt fails too, rethrow that last exception. attempts below 1 is an IllegalArgumentException.
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Interview mode hides the example: solve it from memory, without the hint or the solution, and it counts as solved cold. Progress is saved in your browser, and in your account if you sign in.