What are the effects of exceptions on performance in Java?

Question

Question: Is exception handling in Java actually slow?

Conventional wisdom, as well as a lot of Google results, says that exceptional logic shouldn\'t be used for n

Answer 1

I've done some performance testing with JVM 1.5 and using exceptions was at least 2x slower. On average: Execution time on a trivially small method more than tripled (3x) with exceptions. A trivially small loop that had to catch the exception saw a 2x increase in self-time.

I've seen similar numbers in production code as well as micro benchmarks.

Exceptions should definately NOT be used for anything that's called frequently. Throwing a thousands of exceptions a second would cause a huge bottle neck.

For example, using "Integer.ParseInt(...)" to find all bad values in a very large text file--very bad idea. (I have seen this utility method kill performance on production code)

Using an exception to report a bad value on a user GUI form, probably not so bad from a performance standpoint.

Whether or not its a good design practice, I'd go with the rule: if the error is normal/expected, then use a return value. If it's abnormal, use an exception. For example: reading user inputs, bad values are normal--use an error code. Passing a value to an internal utility function, bad values should be filtered by calling code--use an exception.