[wtp-releng] My Pet Peeve of the week: catch (Throwable

[David M Williams <david_williams@xxxxxxxxxx>]

Some of you may have noticed me changing
your code again. 

This was to fix at least some of our
dangerous exception handling. 

We have HUNDREDS of places where we
"catch (Throwable t)" 
and 1) either do nothing with it ...
the worst mistake or 2) simply log as some error and continue. 
We should do neither. 

There are a few cases where it might
be legitimate to catch a Throwable .. 
one easy rule of thumb, if you do not
re-throw a Throwable, you should not be 
catching it. 

Most of our mis-uses can easily and
safely be changed to "catch (Exception t)" 
and achieve the original intent (This
is a bad enough practice the way we blindly over use it, but 
it is not as bad as catch Throwable).


The danger of catching throwable is
that serious vm conditions are missed, and usually 
surface later as some seemingly unpredictable
error that can not be reproduced. 

An Out of Memory Error is the most common
of these. 

Another common, critical one is "ThreadDeath".
If those are caught and 
not allowed to "surface",
then threads will not be correctly ended. 

So, ... I've done several hundred, but
several hundred remain ... 
please fix up any blind "catch
Throwable" uses in your components. 
Then we'll start on the blind "catch
Exceptions" which are ignored :) 

Just thought I'd explain. 

Thanks,