For a web server under high load, exceptions are extremely expensive to build the stack frame as mentioned below. The rule of thumb is to reserve Exceptions for

For a web server under high load, exceptions are extremely expensive to build the stack frame as mentioned below. The rule of thumb is to reserve Exceptions for Exceptional Circumstances (oom, unable to connect to db etc) and to use a pattern like in this article for un-exceptional exceptions such as required field validation errors. Having done this clean up a few times, it makes a huge difference.