Check whether you have a partial or full component ... I get also
NullPointerExceptions when I try to use a form on a partial component
which is not included in a wrapper.
This can happen as WOLips (at least until beta 2) creates partial
components by default.
cug
womai..ac.com wrote:
> 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 - 23:38:47 EDT