If catching null pointer exception is not a good practice, is catching exception a good one?

Question

I have heard that catching NullPointerException is a bad practice, and i think it is sensibly so. Letting the NullPointerException to propagate to

Answer 1

The 'reason' that catching NullPointerException is considered a bad practice is not because you're supposed to let it bubble up when something goes wrong! Saying any exception is 'best left unhandled' based solely on its type seems like a bad idea.

A NPE is considered the result of a programming error. A strictly correct program should never generate one. The reason seeing it caught is bad is it usually means that the code threw one, and the programmer decided to just catch it and cover it up, rather than fix the broken code that caused it in the first place!

If, for example, you were coupled for business reasons to an API that has a bug inside and occassionally throws a null pointer, it would be perfectly legitimate to catch it, do something about it/inform the user with a better message. Letting 'null' hit the UI just because someone said "Catching Null Pointer Exception is bad" would make no sense!

Catching java.lang.Exception can be legitimate in specific cases, but generally "I'm lazy" is not one of them. :) For example if you're implementing an API and want to make absolutely sure no exception ever comes out of it that isn't in the specification, you might catch Exception and wrap it in some application exception you've defined.