Which is better/more efficient: check for bad values or catch Exceptions in Java

Question

Which is more efficient in Java: to check for bad values to prevent exceptions or let the exceptions happen and catch them?

Here are two blocks of sample code to ill

Answer 1

Normally, one would assume that try-catch is more expensive because it looks heavier in the code, but that entirely depends on the JIT. My guess is that it's impossible to tell without having a real case and some performance measurements. The comparisons could be more expensive, especially when you have many values, for example, or because you have to call equals() since == won't work in many cases.

As for which one you should chose (as in "code style"), my answer is: Make sure that the user gets a useful error message when it fails. Anything else is a matter of taste and I can't give you rules for that.