[Jython-users] jythonc: generated main() signature incorrect

[Owen D. <ow...@ba...>]

I stumbled across the solution: Name my .py file something other than  
RandBoxes.py!

So...if you end up with a weird error from jython looking like:
     1  ./jpywork/RandBoxes.java:216: main(java.lang.String[])
     in RandBoxes cannot override main(java.lang.String[]) in
     processing.core.PApplet; overridden method does not
     throw java.lang.Exception
.. then simply change your .py file to have a different name from the  
class.

Why??  Well, apparently, the .java file created by jythonc includes  
its own main, which has a non-standard main() signature, i.e. throws  
an exception.  So if you're .py file is Foo.py, it basically wraps a  
class Foo around all your jython code, and includes a main() which  
raises an exception.

Thus, if my case, I was building a RandBoxes class subclassing an  
applet class, PApplet, which naturally enough *also* had a standard  
main() static method so it could also be launched as an application.

But because I but my various classes etc in RandBoxes.py, jythonc  
dutifully built a class of that name to encompass all the classes and  
code in the .py file.  One of the classes was named RandBoxes, and,  
also apparently, jythonc "helps you" by merging the outermost class  
utilities into the class name of the same name of the .py file.

Confusing?  You bet.  Simple answer: Don't name your .py file the  
same name as you classes included in the .py file IF one of them also  
subclasses a Java main() method!  Whew!

I'll write this up on my site shortly.

     -- Owen

Owen Densmore   http://backspaces.net