Re: Why shouldn't we catch class RuntimeException?

From:

Patricia Shanahan <pats@acm.org>

Newsgroups:

comp.lang.java.programmer

Date:

Wed, 13 Jun 2007 03:06:11 GMT

Message-ID:

<DaJbi.789$ZY1.630@newsread2.news.pas.earthlink.net>

Lew wrote:

~kurt wrote:

I think you would want to throw an IOException (checked), not a
RuntimeException. Both are Exceptions, but neither inherits from the
the other.

The question of whether to throw a checked or unchecked Exception is
subtle and controversial. Thee suggestion to throw a RuntimeException
for programmer errors and a checked Exception for data or user errors
made sense to me.

I take a slightly different philosophy, though I think it leads to the
same answers.

If the risk of an exception is pervasive in the application, so that
most methods would have to deal with it, then it should be unchecked,
and presumed to be a possibility throughout the application. Making
SomeException extend RuntimeException is a less verbose equivalent of
sticking "throws SomeException" on every method.

If the risk of the exception is localized, so that some methods will
have to deal with it and other can be written assuming they will never
see it, then it should be checked, to make sure the right methods handle it.

Patricia