Also, you don't have to continuously restart the server for every change. Can hot swap code. And for tests there are solutions to keep the jvm running between

Also, you don't have to continuously restart the server for every change. Can hot swap code. And for tests there are solutions to keep the jvm running between the code->test->fix cycle. But I've never felt the need for those, running a single test is often plenty fast as one doesn't need to instantiate the whole app, only the dependencies needed for the test. So plenty fast.