[Jython-users] Howto update "classpath" during runtime?

[Anders D. <and...@st...>]

Hello!

I keep getting exceptions when I try to load (java) classes dynamically into
jython :(

My code is as follows:
...
            // Load jython interpreter with correct classloader
            try {
                String className = "org.python.util.PythonInterpreter";
                ClassLoader loader =
TopManager.getDefault().currentClassLoader();
                Class loaded = loader.loadClass(className);
                pythonInterpreter = (PythonInterpreter)
loaded.newInstance();

                // Add all packages that is mounted in explorer:
                if (PySystemState.packageManager instanceof
SysPackageManager) {
                    SysPackageManager manager = (SysPackageManager)
PySystemState.packageManager;
                    updateJythonClasspath(manager);
                }
...

    private void updateJythonClasspath(SysPackageManager manager) {
        Repository repository = TopManager.getDefault().getRepository();
        FileSystem[] fileSystems = repository.toArray();

        for (int i = 0; i < fileSystems.length; i++) {
            FileSystem fileSystem = fileSystems[i];

            // FIXME: what about non-local filesystems, cvs?
            if (JarFileSystem.class.isAssignableFrom(fileSystem.getClass()))
{
                JarFileSystem jarFile = (JarFileSystem) fileSystem;
                manager.addJar(jarFile.getJarFile().getPath(), true);
            } else if
(LocalFileSystem.class.isAssignableFrom(fileSystem.getClass())) {
                LocalFileSystem localFile = (LocalFileSystem) fileSystem;

manager.addJarDir(localFile.getRootDirectory().getAbsolutePath(), true);
            }
        }
    }

What am I doing wrong, not doing?

thanks in advance
/Anders

Example stack trace:

"# Jython file - http://www.jython.org/
print "hello world!"

from hejsan import *
nada = Nada()
print nada.hej()
"

  File "<string>", line 5, in ?
java.lang.NullPointerException
        at org.python.core.PyJavaClass.setConstructors(PyJavaClass.java)
        at org.python.core.PyJavaClass.initConstructors(PyJavaClass.java)
        at org.python.core.PyJavaClass.__call__(PyJavaClass.java)
        at org.python.core.PyObject.__call__(PyObject.java)
        at org.python.pycode._pyx3.f$0(<string>:5)
        at org.python.pycode._pyx3.call_function(<string>)
        at org.python.core.PyTableCode.call(PyTableCode.java)
        at org.python.core.PyCode.call(PyCode.java)
        at org.python.core.Py.runCode(Py.java)
        at org.python.core.Py.exec(Py.java)
        at org.python.util.PythonInterpreter.exec(PythonInterpreter.java)
        at
org.netbeans.modules.scripting.JPythonScriptType.exec(JPythonScriptType.java
:154)
        at
org.netbeans.modules.scripting.AbstractScriptType.exec(AbstractScriptType.ja
va:140)
        at org.openide.execution.ScriptType.exec(ScriptType.java:80)
        at
org.netbeans.modules.scripting.ScriptSupport$1.run(ScriptSupport.java:72)
        at
org.netbeans.core.execution.RunClassThread.run(RunClassThread.java:118)
java.lang.NullPointerException: java.lang.NullPointerException
        at org.python.core.Py.JavaError(Py.java)
        at org.python.core.PyTableCode.call(PyTableCode.java)
        at org.python.core.PyCode.call(PyCode.java)
        at org.python.core.Py.runCode(Py.java)
        at org.python.core.Py.exec(Py.java)
        at org.python.util.PythonInterpreter.exec(PythonInterpreter.java)
        at
org.netbeans.modules.scripting.JPythonScriptType.exec(JPythonScriptType.java
:154)
        at
org.netbeans.modules.scripting.AbstractScriptType.exec(AbstractScriptType.ja
va:140)
        at org.openide.execution.ScriptType.exec(ScriptType.java:80)
        at
org.netbeans.modules.scripting.ScriptSupport$1.run(ScriptSupport.java:72)
[catch] at
org.netbeans.core.execution.RunClassThread.run(RunClassThread.java:118)