VirtualEnv Python as Java PythonInterpreter in MacOS

Question

I'm currently finding a way to get some output from a python script through Java. After finding jython, I used PythonInterpreter to send parameters and receive output I expect.

My Code

    PythonInterpreter interpreter = new PythonInterpreter();
    String fileUrlPath = "/Users/me/Desktop/";
    String scriptName = "pythonScript";
    interpreter.exec("import sys\n" + "import os \n" + "sys.path.append('" + fileUrlPath + "')\n"+ "from "+scriptName+" import * \n");
    String funcName = "predictionFunction";
    PyObject someFunc = interpreter.get(funcName);

    try 
    {
        PyObject out = someFunc.__call__(new PyString(pathToImageFolder), new PyString(fileName));
        System.out.println(out);
    } 
    catch (PyException e) 
    {
        e.printStackTrace();
    }

My Problem

But whenever I launch my program, It shows, numpy module not found error. So I checked the python version and it showed 2.7.0 which is version of jython python interpreter.

But all my python libraries has been installed in a Virtual environment in path path/to/vir/env/bin . So I need to change the interpreter of java PythonInterpreter function to the python I've installed in my virtual environment.

is it possible? If so, really appreciate if someone can help.

Answer 1

What you're asking for is impossible.

Jython can't use C-API extensions, which includes NumPy. Changing the sys.path to include the location where you installed NumPy won't help.

Jython can use Java packages, and there are Java packages for array-based numerics, but none of them is anywhere near a drop-in replacement for NumPy; you'd have to rewrite all of your code to use a pretty different API, and it may not have features you're relying on.

---

However, if all you're trying to do is call some Python code with some simple string arguments and get back a string as output, you can do that just by running CPython as a subprocess. And it seems like that's exactly what you're doing: you've got some wrapper code that just imports your module, calls a function with two strings, and prints out the return value as a string.

Step 1: Wrap that Python code up in a script that takes its arguments via sys.argv , and outputs its results via print .

Step 2: Run your script with the normal CPython interpreter from the virtualenv that has NumPy installed, and capture its output with a pipe.

Step 3: There is no step 3. (Or was it something something life finds a chaos theory because Earth girls are easy? I don't know, it's all Jeff Goldblum.)