I'm working my way through Apple's Web Apps book, and have run into my
first debugging challenge. I'm in Chapter 7, the Component
Communication exercise.
I'm getting a java.lang.NullPointerException when I hit the submit
button, but that's not really the problem. The problem is that I'm
trying to figure out how to debug this, and it's eluding me. I had no
problems with the basic stuff, setting breakpoints and stepping through
code. But I'm not sure what to do with this error.
I have a function called submitChanges bound to the submit button, and
I put a breakpoint on the first line, but it's never getting there.
The stack trace in the console window (I'm using Eclipse 3) looks like
this (there's more of it but I figured this was enough):
[2004-08-24 22:33:08 EDT] <WorkerThread0>
<com.webobjects.appserver._private.WOComponentRequestHandler>:
Exception occurred while handling request:
java.lang.NullPointerException
[2004-08-24 22:33:08 EDT] <WorkerThread0> java.lang.NullPointerException
at
com.webobjects.appserver._private.WOForm._enterFormInContext(WOForm.java
:58)
at
com.webobjects.appserver._private.WOForm.takeValuesFromRequest(WOForm.ja
va:69)
The source for WOForm.class and WOComponent.class aren't able to be
found by Eclipse, and I don't know if it's a configuration snafu on my
part or if we just treat those as magic black boxes.
So my question is, how do I go about figuring out where my error is?
I'll gladly RTFM, I just can't find an appropriate FM to R. I have
already looked at the debugging help in Eclipse but it wasn't detailed
enough for this situation (or for my state of newbieness, take your
pick :).
thanks,
janine
PS thanks to the several people who posted and e-mailed me about how to
get past the "does not contain a main type" error. Baby steps... ;)
This archive was generated by hypermail 2.0.0 : Tue Aug 24 2004 - 23:01:07 EDT