Calling java program from python

I would suggest using the class ProcessBuilder to implement a non-trivial solution that includes communication. Generating Python code on the fly is a cool thought, but is it really valuable? Most problems that I see involve invoking a sub-process that solves a problem or class of problems ; the code is well developed and debugged, so hoisting to Java or C is not considered valuable.

As for the return value, there are a few options: Capture the printed output of the Python program. Have the Python program write the desired output to a well-defined file, and just ignore all other output. Check sub-process return status and act accordingly.

You might want to use an embedded Python interpreter as part of a web page that executes user entered Python in a restricted environment. Cheers, Oralloy! Any idea how to capture that as well. Thank you for classifying different methods of calling Python from Java. I wonder if you have some thoughts about the following: 1 If you use Runtime or ProcessBuilder, is there a way to keep python running between calls and submit new commands to the existing process? I get "Exception in thread "main" ImportError: Cannot import site module and its dependencies: No module named site".

The solution for first Runtime,Saved my day :. Post Reply. Similar topics PHP. Success using Python. NET with py2exe?

The interpreter adds the builtin globals to the globals passed in, then executes the script. The same map may be used for both the locals and the globals - this mode may seem more familiar to those who regularly script in Python and expect the import statement to have a global effect.

There is no eval method. You can retrieve values by passing a container object such as an array or map as one of the locals and you can set elements in the object with values to be returned. You may want to maintain references to Python objects across script executions.

The following functions let a Java caller refer to a Python value which can be a base type or an object via a token which may be exchanged for the value at any time. OMG this method is not for the faint of heart. And I can tell you it has taken me very long to achieve this in with a decent method.

Main reason you would want to do this is so that you can run cpython code which as full rein over you java object. There are major major things to consider before deciding to try and bread java which is like a chimp with python which is like a horse. Firstly if you crash the interpreter that's lights out for you program!

And don't get me started on concurrency issues! In addition, there is allot allot of boiler, I believe I have found the best configuration to minimize this boiler but still it is allot! Good that you know that now.

Just write your object as if your program as in cpp not java, with the data you want to access from both worlds. Get this working first, then move on to the hard part! To get to python you need to embed an interpreter. Once you have that working, its time to make the horse and the monkey dance!

I know I have not given you the fish, merely told you where to find the fish. Some pointers to note for this when compiling. When you compile boost you will need to compile a shared library. And you need to include and link to the stuff you need from jdk, ie jawt. And yeah full on I know. There are so many ways in which this can go sour. So make sure you get each thing done block by block. Please take a look on similar question and read the answer.

Add a comment. Active Oldest Votes. Paul Verest Voo Voo I've installed JYthon, or i assume i did, and I keep trying to run the code that you outlined but it highlighted as a mistake. Does the installion of Jython need to go to a specific folder, either in the python or java folders? There aren't any error, i'm just having a hard time integrating Jython into Netbeans — Shahab. If there's no error it would work, so that's obviously not the case ; "Error" does not mean runtime error, could be a compile error as well.

Python 2 end of Life is 1. Best simplest Option is the Jep lib — Flummiboy. That's too bad. Show 8 more comments.

So I have played with the following methods, and listed them from easy to difficult: Java to Jython Advantages: Trivially easy. Advantages: Access to cpython, not as difficult as following methods Disadvantages: Cannot change the member data of java objects directly from python. Dharman Derrops Derrops 6, 4 4 gold badges 23 23 silver badges 47 47 bronze badges.

Here a library that lets you write your python scripts once and decide which integration method Jython, CPython via Jep and Py4j to use at runtime: github. I encourage you to write an answer I would upvote it. I dislike the top answer haha because I don't think it provides much useful information outside of a google search.

I created a separate answer — subes. Peiming Hu Peiming Hu 4 4 silver badges 8 8 bronze badges. If you cannot define such an interface, then this design approach doesn't suits. Wildhammer Wildhammer 1, 1 1 gold badge 21 21 silver badges 24 24 bronze badges.

This project doesn't have any release. ChristianSchlichtherle invesdwin-context-python version 1. Project release are now available, see github. Anurag Uniyal Anurag Uniyal Timo Timo 4, 3 3 gold badges 32 32 silver badges 38 38 bronze badges. I used that for a project 15 years ago and it was murderously complicated. At least use JSON.. Any language that itself can be called from c that is. It's not that trivial to write the code to call python functions from c.

Jython has some limitations: There are a number of differences. Community Bot 1 1 1 silver badge. Flummiboy Flummiboy 1 1 gold badge 4 4 silver badges 19 19 bronze badges.