I'm getting an InvalidJarIndexException when trying to utilize Jython standalone JAR inside my application and I'm unable to figure out what I'm doing wrong.
As soon as I attempt to execute a Python script with an import statement for any Java class from a package starting with "com.", e.g.: "com.foo.Bar", the following exception is thrown (truncated):
Traceback (most recent call last):
File "<string>", line 1, in <module>
sun.misc.InvalidJarIndexException: Invalid index
at sun.misc.URLClassPath$JarLoader.getResource(URLClassPath.java:1152)
at sun.misc.URLClassPath$JarLoader.getResource(URLClassPath.java:1062)
at sun.misc.URLClassPath$JarLoader.findResource(URLClassPath.java:1032)
at sun.misc.URLClassPath.findResource(URLClassPath.java:225)
at java.net.URLClassLoader$2.run(URLClassLoader.java:572)
at java.net.URLClassLoader$2.run(URLClassLoader.java:570)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findResource(URLClassLoader.java:569)
at java.lang.ClassLoader.getResource(ClassLoader.java:1089)
at java.net.URLClassLoader.getResourceAsStream(URLClassLoader.java:233)
at org.python.core.ClasspathPyImporter.tryClassLoader(ClasspathPyImporter.java:221)
at org.python.core.ClasspathPyImporter.makeEntry(ClasspathPyImporter.java:208)
at org.python.core.ClasspathPyImporter.makeEntry(ClasspathPyImporter.java:18)
at org.python.core.util.importer.getModuleInfo(importer.java:174)
at org.python.core.util.importer.importer_find_module(importer.java:98)
at org.python.core.ClasspathPyImporter.ClasspathPyImporter_find_module(ClasspathPyImporter.java:134)
at org.python.core.ClasspathPyImporter$ClasspathPyImporter_find_module_exposer.__call__(Unknown Source)
at org.python.core.PyBuiltinMethodNarrow.__call__(PyBuiltinMethodNarrow.java:48)
at org.python.core.imp.find_module(imp.java:761)
at org.python.core.imp.import_next(imp.java:1158)
at org.python.core.imp.import_module_level(imp.java:1350)
at org.python.core.imp.importName(imp.java:1528)
at org.python.core.ImportFunction.__call__(__builtin__.java:1285)
at org.python.core.PyObject.__call__(PyObject.java:433)
at org.python.core.__builtin__.__import__(__builtin__.java:1232)
at org.python.core.imp.importOneAs(imp.java:1564)
at org.python.pycode._pyx0.f$0(<string>:1)
at org.python.pycode._pyx0.call_function(<string>)
at org.python.core.PyTableCode.call(PyTableCode.java:173)
at org.python.core.PyCode.call(PyCode.java:18)
at org.python.core.Py.runCode(Py.java:1687)
at org.python.core.Py.exec(Py.java:1731)
at org.python.util.PythonInterpreter.exec(PythonInterpreter.java:268)
at com.so.Script.execute(Script.java:20)
Here's all I'm doing in my code (I'm actually invoking this via a Swing action on a JMenuItem calling new Script().execute(), which is most likely irrelevant):
package com.so;
import org.python.core.PyDictionary;
import org.python.core.PySystemState;
import org.python.util.PythonInterpreter;
public class Script {
public Script() {
}
public void execute() {
PyDictionary table = new PyDictionary();
PySystemState state = new PySystemState();
PythonInterpreter interp = new PythonInterpreter(table, state);
String script;
script = "" +
"import com.foo.Bar as Bar\n" +
"";
interp.exec(script);
}
}
It doesn't even matter that there is no such package/class in my classpath. But what baffles me the most is that when I, thinking this has to be classpath related, created a separate mock project with the exact same classpath (same JAR files from the same locations on disk), the other project works just fine when run and it executes the actual script.
What could I be doing wrong here?
This happens with Java 1.8u241 (x64) and both jython-standalone-2.7.2.jar and an earlier 2.7.1 version. The ClassLoader in the stack trace is attempting to resolve "com".
I found the culprit entirely by accident.
My broken project used an older (ancient) version of the Glazed Lists library, namely glazedlists-1.8.0_java15.jar. This JAR seems to be directly incompatible with jython-standalone-2.7.2.jar. As soon as you put them on the same classpath and attempt to execute a python script, which imports any Java package starting with "com.", you end up with an InvalidJarIndexException. Updating to a newer version of said JAR resolved the issue.
Therefore, if you encounter a similar exception trying to run Jython, I suggest you update all dependencies of your project to latest or newer versions of them. In fact this would probably be the solution, even if not using Jython at all.