Re: Potential Software Failure

I don't have the file which has the problem here
(forgot to check it into CVS yesterday.)

The code that it generates is exactly like I said
before.  (Written so as not to be confusing about
the catch block.  Positions made up.)


0   ACONST_NULL
1   ICONST( 0 )
2   INVOKEVIRTUAL ( runTest(I)I )
3   ICONST( 0 )
4   IRETURN
5   ICONST( 0 )
6   IRETURN

CATCH: From 0
         To 4
    Handler 5
        Exc java.lang.NullPointerException

The catch block is on the InstructionList, so
that isn't the problem.

The code is supposed to do the following:
  Call "runTest(I)I" on NULL.
  Catch the NullPointerException.
  Return 0 from the handler.

It definitely throws the NPE, and it never
gets caught.  (Once again, looking at the Method
that was generated, it didn't have any catch tables.)

DDP


--- Markus Dahm <[email protected]> wrote:
> David Dixon-Peugh wrote:
> 
> > I have found what I believe to be a bug in BCEL,
> > and would like to see if anyone else has seen
> > this in the wild.
> > 
> > Basically, I'm generating code that looks like
> this:
> >   ACONST_NULL
> >   ICONST( 0 )
> >   INVOKEVIRTUAL ( runTest(I)I )
> >   ICONST( 0 )
> >   IRETURN
> > [catch NullPointerException]
> >   ICONST( 0 )
> >   IRETURN
> > 
> > The idea is to force a NullPointerException to be
> > raised, and then catch it with a Catch clause.
> > 
> > This is being done in a MethodGen object, using
> > "addExceptionHandler(...)" to create the 
> > CodeExceptionGen inside the MethodGen.  (Adding a
> > CodeExceptionGen is a good idea.  We should be
> able
> > to do that directly.)
> 
> 
> Hmm. Maybe :)
> 
>  
> > When the MethodGen.getMethod() is called, if you
> take
> > a look at the "getExceptionTable()" result, you 
> > basically get nothing.  (Catch table wasn't
> written
> > to Method.)
> 
> 
> Where is the code of the exception handler, i.e,
> have you short example of your code.
> 
> Cheers
> 	Markus
> 
> 
> 
> 
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