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https://github.com/bcdev/jpy

A bi-directional Python-Java bridge used to embed Java in CPython or the other way round.
https://github.com/bcdev/jpy

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A bi-directional Python-Java bridge used to embed Java in CPython or the other way round.

Awesome Lists containing this project

README 

        
[![Build Status](https://ci.appveyor.com/api/projects/status/ywkcey4nlt0avasf?svg=true)](https://ci.appveyor.com/project/bcdev/jpy)

[![Documentation Status](https://readthedocs.org/projects/jpy/badge/?version=latest)](http://jpy.readthedocs.org/en/latest/?badge=latest)



---



### :bangbang: We moved to [jpy-consortium/jpy](https://github.com/jpy-consortium/jpy)



jpy is now being further developed in a dedicated GitHub organision maintained by members 

of the companies [DeepHaven](https://deephaven.io/) and [Brockmann Consult](https://www.brockmann-consult.de/).

This repo will soon be archived. Please use the new [jpy-consortium/jpy](https://github.com/jpy-consortium/jpy)

for any issues or PRs, thanks!



---



jpy - a Python-Java Bridge

==========================



jpy is a **bi-directional** Python-Java bridge which you can use to embed Java

code in Python programs or the other way round. It has been designed

particularly with regard to maximum data transfer speed between the two

languages.  It comes with a number of outstanding features:



* Fully translates Java class hierarchies to Python

* Transparently handles Java method overloading

* Support of Java multi-threading

* Fast and memory-efficient support of primitive Java array parameters via

  [Python buffers](http://docs.python.org/3.3/c-api/buffer.html)

  (e.g. [Numpy arrays](http://docs.scipy.org/doc/numpy/reference/arrays.html))

* Support of Java methods that modify primitive Java array parameters (mutable

  parameters)

* Java arrays translate into Python sequence objects

* Java API for accessing Python objects (`jpy.jar`)



jpy has been tested with Python 3.4–3.8 and OpenJDK 8 on 64-bit Ubuntu Linux,

Windows 10, and macOS.



The initial development of jpy was driven by the need to write Python

extensions to an established scientific imaging application programmed in

Java, namely the [SNAP](http://step.esa.int/) toolbox, the SeNtinel

Application Platform project, funded by the [European Space

Agency](http://www.esa.int/ESA) (ESA). (jpy is bundled with the SNAP

distribution.)



Writing such Python plug-ins for a Java application usually requires a

bi-directional communication between Python and Java since the Python

extension code must be able to call back into the Java APIs.



For more information please have a look into jpy's



* [documentation](http://jpy.readthedocs.org/en/latest/)

* [source repository](https://github.com/bcdev/jpy)

* [issue tracker](https://github.com/bcdev/jpy/issues?state=open)



How to build wheels for Linux and Mac

-------------------------------------



Install a JDK 8, preferably the Oracle distribution. Set `JDK_HOME` or

`JPY_JDK_HOME` to point to your JDK installation and run the build script:



    $ export JDK_HOME=

    $ export JAVA_HOME=$JDK_HOME

    $ python setup.py build maven bdist_wheel



On success, the wheel is found in the `dist` directory.



To deploy the `jpy.jar` (if you don't know why you need this step, this is not

for you)::



    $ mvn clean deploy -DskipTests=true



How to build a wheel for Windows

--------------------------------



Set `JDK_HOME` or `JPY_JDK_HOME` to point to your JDK installation. You'll

need Windows SDK 7.1 or Visual Studio C++ to build the sources. With Windows

SDK 7.1::



    > SET VS90COMNTOOLS=C:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\Tools\

    > SET DISTUTILS_USE_SDK=1

    > C:\Program Files\Microsoft SDKs\Windows\v7.1\bin\setenv /x64 /release

    > SET JDK_HOME=

    > python setup.py build maven bdist_wheel

    

With Visual Studio 14 and higher it is much easier::



    > SET VS100COMNTOOLS=C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\Tools\

    > SET JDK_HOME=

    > python setup.py build maven bdist_wheel



On success, the wheel can be found in the `dist` directory.



How to install from sources

---------------------------



TBD



Releasing jpy

-------------



The target reader of this section is a jpy developer wishing to release a new

jpy version.  Note: You need to have Sphinx installed to update the

documentation.



1. Make sure all Java *and* Python units tests run green

2. Remove the `-SNAPSHOT` qualifier from versions names in both the Maven

   `pom.xml` and `setup.py` files, and update the version numbers and copyright

   years in `jpyutil.py` and `doc/conf.py`.

3. Generate Java API doc by running `mvn javadoc:javadoc` which will update

   directory `doc/_static`

4. Update documentation, `cd doc` and run `make html` 

5. http://peterdowns.com/posts/first-time-with-pypi.html



Automated builds

----------------



As of 2020-08-27, [Python wheel](https://pythonwheels.com/) packages for jpy

are automatically built on

[AppVeyor](https://ci.appveyor.com/project/bcdev/jpy), but at present they are

uploaded only to a private FTP server and not publicly released. Wheels are

built for Python versions 3.4, 3.5, 3.6, 3.7, and 3.8 on Linux, Windows, and

macOS (≥10.9). Only 64-bit wheels are built.



The repository also contains an outdated configuration for [automated Travis

builds](https://travis-ci.org/github/bcdev/jpy), but this configuration is

currently unmaintained and broken.