JPype class not found

问题:

JPype is an amazing project since I allows to instantiate a JVM directly from Python.

Unfortunately, I got stuck in the first baby steps.

I have A.java source code (located in C:\tmp folder):

class A {
    public A() {
        super();
    }
    public String sayHi() {
        return("Hello");
    }
}

Which was compiled to a class, using: javac A.java

Thus, A.class is located in C:\tmp folder.

I have the following Python source code:

import os
import jpype
jpype.startJVM(jpype.getDefaultJVMPath(), '-ea', '-Djava.class.path=c:\\tmp')
A = jpype.JClass("A")
a = A()
print a.sayHi()
jpype.shutdownJVM()

When I run it, I get the error below:

C:\tmp>jpype_test.py
Traceback (most recent call last):
  File "C:\tmp\jpype_test.py", line 10, in <module>
    A = jpype.JClass("A")
  File "C:\Python27\lib\site-packages\jpype\_jclass.py", line 54, in JClass
    raise _RUNTIMEEXCEPTION.PYEXC("Class %s not found" % name)
jpype._jexception.ExceptionPyRaisable: java.lang.Exception: Class A not found

Since I can't find the A class, it is probably an issue related to CLASSPATH, but I can't realize what I am doing wrong.

Any clues?

EDIT 1:

The problem persists. But, just to add to my question, if I use native java libraries, like: java.util, the code runs WITHOUT errors. For example, the code below works:

import jpype
jpype.startJVM(jpype.getDefaultJVMPath())
util = jpype.JPackage("java.util")
al = util.ArrayList()
al.add(1)
al.add(2)
print al.size()
jpype.shutdownJVM()

And returns 2.

EDIT 2:

Issue solved, see answer below...

回答1:

I solved the problem and I would let the answer here for the records.

1) Nothing was wrong with the source code.

2) Problem was that my Python was 32 bits and my java sdk (including the javac bytecode compiler) was 64 bits. I uninstalled the java sdk and re-installed a 32bits version. Done! Solved!

回答2:

Try to change your path like this:

    jpype.startJVM(jpype.getDefaultJVMPath(), '-ea', '-Djava.class.path=c:\\tmp\')