[Jython-users] Using Jython to compile a script and run it from a jar

[Connor, A. J <ada...@au...>]

(Some of the stacktrace elided to avoid the need for moderation on message length.)

Hi, fellow Jython users. I'm hoping that someone with a better understanding of Jython internals than I can help me out.

This question is related to the article "Distributing Jython Scripts" at http://wiki.python.org/jython/JythonFaq/DistributingJythonScripts

What I'm trying to do: execute some Django functionality from django.template, and, I hope, package it all up in a jar so that we can use it from an existing Java program. (Why Django instead of something else? Because we use Django for Python, and this is related to making an older, legacy product more compatible.)

The test.py script below is a simplified version that triggers the bug I'm hitting.

What I've done:

1.      copied jython.jar to "jythonall.jar"

2.      copied the various Python packages in Lib/ into the jar - in particular, django.

3.      compiled my test script using jython -m py_compile test.py (results in test$py.class)

4.      Added test$py.class to the jar.

Test Results:
test.py:
import django.template
print 'done'
If I run the command java -cp .\jythonall.jar org.python.util.jython test.py, it works as expected and prints "done".

But if I run the command java -cp .\jythonall.jar test$py, I get the following stacktrace. My question is: Why? What do I need to do for it to work?

Stacktrace:
Documents\jython_templates\jythonall.jar'
Exception in thread "main" Traceback (most recent call last):
  File "test2$py", line 1, in <module>
  File "__pyclasspath__/django/template/__init__$py.class", line 53, in <module>

  File "__pyclasspath__/inspect.py", line 31, in <module>
  File "__pyclasspath__/string$py.class", line 122, in <module>
  File "__pyclasspath__/string$py.class", line 115, in __init__
  File "__pyclasspath__/re$py.class", line 214, in escape java.lang.NullPointerException
        at org.python.core.PyObject._add(PyObject.java:1994)
        at re$py.escape$11(C:\jython2.5.2rc3\Lib\re.py:215)
        at re$py.call_function(C:\jython2.5.2rc3\Lib\re.py)
        at org.python.core.PyTableCode.call(PyTableCode.java:165)
... (elided)
        at org.python.core.PyTableCode.call(PyTableCode.java:165)
        at org.python.core.PyCode.call(PyCode.java:18)
        at org.python.core.imp.createFromCode(imp.java:386)
        at org.python.core.imp.createFromCode(imp.java:357)
        at org.python.core.Py.runMain(Py.java:950)
        at test2$py.main(C:\Documents and Settings\adamc\My Documents\jython_templates\test2.py)

java.lang.NullPointerException: java.lang.NullPointerException

BTW, other Django imports work, so I suspect it might be something particular to django.template's __init__.py.

Thanks in advance for any help!

adam connor / Financial Information Systems, The University of Texas at Austin