Need authoritative source for why you shouldn't throw or catch java.lang.Exception

Question

I've got a coding standards meeting in just over an hour and I need a quick answer to this one.

Common wisdom among experienced Java programmers is that you don't throw or catch java.lang.Exception (with rare exceptions - no pun intended). The reason you don't do this is that the statement

catch (java.lang.Exception ex) {...}

will also catch unchecked Exceptions, and in most cases this is not what is intended.

We already have a lot of legacy code written by existing team members where they catch a subclass of java.lang.Exception, log an error, and rethrow the subclass as java.lang.Exception.

I need to convince them that

1. They need to stop writing code like this.
2. Existing code that uses this anti-pattern needs to be fixed

Number 2 means a fair amount of refactoring.

It will shorten the argument at the meeting if I can show an article or blog entry by one of the Java community heavyweights that makes this point (i.e. Joshua Bloch, James Gosling). My google-fu hasn't turned up anything so far.

Does anyone know of an article or blog by a respected Java guru that says that you shouldn't throw or catch java.lang.Exception?

Quick answers are much appreciated.

Dean

Answer 1

Here's something: Java Tip 134: When catching exceptions, don't cast your net too wide (JavaWorld)

Effective Java (Second Edition) by Joshua Bloch might have something on this in Chapter 9 (Exceptions), although I couldn't quickly find anything about not catching Exception.

Here is a Q&A from JavaWorld about the question (also points to Java Tip 134) - it also explains why you sometimes have to break the rule of not catching Exception or even Throwable.

Answer 2

See this article from Brian Goetz (the concurrency wizard) who has his own insight as well as quoting Josh Bloch in Effective Java