[Jython-users] ExceptionInInitializerError when running example code

[Sandra J. <san...@gm...>]

Dear All,

I am new to Jython and decided to try the code supplied in the monthly
Newsletters of September and October 2006 as I want to be able to write some
object factories for Python classes.

I am coding and testing in Eclipse vsn 3.5.1 with PyDev plugin installed,
Jython 2.5.1 and JRE 6

I copied the code from the newsletters and changed the classes that differed
between the two newsletters to have either Sep or Oct in them to distinguish
where they came from. I have spent ages trying to find the problem and
getting nowhere. One suggestion in an earlier post was to include into the
python class

import sys
sys.add_package(' java package' ) - so I added this code as well for the
java package 'jyinterface.interfaces'

but to no avail, same NullPointerException & ExceptionInInitializerError.

The only differences between my code and the code provided by Charlie Groves
and Josh Juneau are java class name changes (MainSep.java, MainOct.java in
package jyinterface.interfaces, EmployeeOct.py and EmployeeSep.py in the
Jython project and I put MainSep.java not in package jyinterface as Josh
had, but in the jyinterface.interfaces package). I also updated the
references to these classes.

Here is the console output I get. Happy to supply the code if anyone feels
kind enough to have a look!

Exception in thread "main" java.lang.ExceptionInInitializerError
    at org.python.core.PyObject.<clinit>(PyObject.java:26)
    at org.python.util.PythonInterpreter.<init>(PythonInterpreter.java:72)
    at org.python.util.PythonInterpreter.<init>(PythonInterpreter.java:60)
    at jyinterface.factory.EmployeeFactory.<init>(EmployeeFactory.java:13)
    at jyinterface.interfaces.MainOct.main(MainOct.java:18)
Caused by: java.lang.NullPointerException
    at org.python.core.PyType.init(PyType.java:458)
    at org.python.core.PyType.createType(PyType.java:1175)
    at org.python.core.PyType.addFromClass(PyType.java:1116)
    at org.python.core.PyType.fromClass(PyType.java:1182)
    at org.python.core.PyType.<clinit>(PyType.java:30)
    ... 5 more

The lines that are being referred to in the error log are

MainOct.java:18
        EmployeeFactory factory = new EmployeeFactory();
EmployeeFactory.java:13
        PythonInterpreter interpreter = new PythonInterpreter();
PythonInterpreter.java:60

public PythonInterpreter() {    // line 59
        this(null, null);                   // line 60

PythonInterpreter.java:72
            dict = new PyStringMap();
PyObject.java:26
    public static final PyType TYPE = PyType.fromClass(PyObject.class);


PyType.java:458
            if (!Py.BOOTSTRAP_TYPES.contains(underlying_class)) {
PyType.java:1175
        newtype.init(c,needsInners);
PyType.java:1116
        return createType(c, needsInners);
PyType.java:1182
            addFromClass(PyType.class, null);
PyType.java:30
    public static PyType TYPE = fromClass(PyType.class);

Cheers,
Sandra