Re: Catching NPEs
Frank wrote:
"Daniel Dyer" <"You don't need it"> wrote in message
news:op.tk8ogdwu8kxvgr@jack.local...
On Wed, 27 Dec 2006 22:06:23 -0000, Frank <frank@nospam.heaven.com> wrote:
Is it possible to catch (and hence respond to) Null Pointer Exceptions
that
could occur anywhere within my application? I thought of wrapping the
main() method in a try/catch block catching Exception or something along
those lines but I can't see how to get it to work.
You can, but why would you want to? NullPointerExceptions are generally
bugs that need to be fixed by changing the code. Even if you catch them,
how will you recover? You won't know which reference was null so doing
anything meaningful is pretty much impossible.
This method will help you deal with unexpected exceptions:
<http://java.sun.com/j2se/1.5.0/docs/api/java/lang/Thread.html#setDefaultUncaughtExceptionHandler(java.lang.Thread.UncaughtExceptionHandler)>
Thanks. The reason I wanted to catch these exceptions is so I could log
them. It's one thing to have your IDE handle exceptions for you but when
the application is deployed to the field you need to know what exceptions
they get. This method you quoted to set the default uncaught exception
handler is just what I was looking for.
-F
A noble cause indeed. You may also wish to open a JDialog (assuming a
GUI application) which alerts to the user that a problem occured. Just
don't give them too much detail unless they ask for it though.
setDefaultUncaughtExceptionHandler is definetly the way to go in order
to detect uncaught exceptions. It will catch almost all
RuntimeExceptions and Errors. I have had issues catching
OutOfMemoryException, but the JVM is often a in a pretty big fubar
state by that time.
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