Package: jpy
jpy - a Python-Java Bridgejpy is abi-directionalPython-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 PythonTransparently handles Java method overloadingSupport of Java multi-threadingFast and memory-efficient support of primitive Java array parameters viaPython buffers(e.g.Numpy arrays)Support of Java methods that modify primitive Java array parameters (mutable
parameters)Java arrays translate into Python sequence objectsJava 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 theSNAPtoolbox, the SeNtinel
Application Platform project, funded by theEuropean Space
Agency(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'sdocumentationsource repositoryissue trackerHow to build wheels for Linux and MacInstall a JDK 8, preferably the Oracle distribution. SetJDK_HOMEorJPY_JDK_HOMEto point to your JDK installation and run the build script:$ export JDK_HOME=<your-jdk-dir>
$ export JAVA_HOME=$JDK_HOME
$ pip install setuptools wheel
$ python setup.py build maven bdist_wheelOn success, the wheel is found in thedistdirectory.To deploy thejpy.jar(if you don't know why you need this step, this is not
for you)::$ mvn clean deploy -DskipTests=trueHow to build a wheel for WindowsSetJDK_HOMEorJPY_JDK_HOMEto 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=<your-jdk-dir>
> pip install setuptools wheel
> python setup.py build maven bdist_wheelWith 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=<your-jdk-dir>
> pip install setuptools wheel
> python setup.py build maven bdist_wheelOn success, the wheel can be found in thedistdirectory.How to install from sourcesTBDReleasing jpyThe 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.Make sure all JavaandPython units tests run greenRemove the-SNAPSHOTqualifier from versions names in both the Mavenpom.xmlandsetup.pyfiles, and update the version numbers and copyright
years injpyutil.pyanddoc/conf.py.Generate Java API doc by runningmvn javadoc:javadocwhich will update
directorydoc/_staticUpdate documentation,cd docand runmake htmlhttp://peterdowns.com/posts/first-time-with-pypi.htmlAutomated buildsAs of 2020-08-27,Python wheelpackages for jpy
are automatically built onAppVeyor, 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 forautomated Travis
builds, but this configuration is
currently unmaintained and broken.Code Of ConductThis project has adopted theContributor Covenant Code of Conduct.
For more information see theCode of Conductor contactopencode@deephaven.iowith any additional questions or comments.ContributingFor instructions on contributing, seeCONTRIBUTING.md.NotesSome of the details on this README are out of date. Efforts to improve them will be made in the future.jpy ChangelogVersion 0.15.0#112Add jpy.byte_buffer() function#119Fix Mac OSX + OpenJDK builds whereJAVA_HOMEcontainslibexecbut notlib#121Python 3.12 build#109Add aarch64 Linux wheels to build / release workflow#113Update build.yml actionsVersion 0.14.0#99Check for exception in getInt/Long/DoubleValue()#104PyDictWrapper.values() incorrectly close the underlying PyObject while it is still referencedVersion 0.13.0#96Python 3.11 compatibilityVersion 0.12.0#88Use valueOf() to box primitive values instead of creating new objects every time#89Add Java process lookup for 'java.home' in find_jvm_dll_file()#85Support creation of zero-sized primitive Java arraysVersion 0.11.1#79Produce usable / distributable macosx wheelsVersion 0.11.0Publish artifacts toPyPi. Source tarball and binary wheels for Python 3.6 - 3.10 for Linux, Mac, and Windows (x86_64).Publish release to Maven Central with group idorg.jpyconsortiumand artifact idjpy. Java-8 compatible jars.Many more changes.Version 0.10Add the ability to pass properties and options to write_config_files. These values get passed
to the jvm when it is initialized.#180Contribution by davidlehrian.Make jpy work with Anaconda by setting environment variablePYTHONHOMEfrom Java#143. Contribution by Dr-Irv.Fixed: Constants are not properly passed from Java to Python when using interfaces#140. Contribution by Dr-Irv.Fixed: Cannot iterate through a dict in Python 3.x#136. Contribution by Dr-Irv.Automatically build 64-bit Python wheels for all Python versions from 3.4 to
3.8 on Linux, Windows, and Mac (fixes#174).Version 0.9This version includes a number of contributions from supportive GitHub users. Thanks to all of you!FixesCorrected Java reference count of complex PyObject passed back and forth to methods (issue #120). Fix by sbarnoud.Fixed problem where default methods on Java 8 Interfaces were not found (issue #102). Fix by Charles P. Wright.Fixed error caused by missingsys.argvin Python when called from Java (issue #81). Fix by Dave Voutila.Fixed problem where calling jpy.get_type() too many times causes a memory access error (issue #74). Fix by Dave Voutila.Fixed a corruption when retrieving long values (#72). Fix by chipkent.Fixed fatal error when stopping python session (issue #70, #77). Fix by Dave Voutila.Explicit null checks for avoiding JVM crash (issue #126). Fix by Geomatys.ImprovementsCan now use pip to install Pythonjpypackage directly from GitHub (#83).
This works for Linux and OS X where C compilers are available by default
and should work on Windows with Visual Studio 15 installed.
Contribution by Dave Voutila.JavaPyObjectis now serializable. Contribution by Mario Briggs.Improved Varargs method matching.  You may pass in either an array (as in the
past) or individual Python arguments, the match for a varargs method call is
the minimum match for each of the arguments. Zero length arrays (i.e. no
arguments) are also permitted with a match value of 10.jpy.type_translationsdictionary for callbacks when instantiating Python objects.jpy.VerboseExceptionsenables full Java stack traces.More Python exceptions are translated to the corresponding Java type.Globals and locals are converted when executing code with PyLib, to allow variables to be
used across statement invocation; and interrogated from Java.PyObject wrappers for dictionary, list, and introspection functions to tell
you whether or not you can convert the object.Support for isAssignable checks when dealing with Python Strings and primitives, to allow
matches for argument types such asjava.lang.Comparableorjava.lang.Number.Version 0.8FixesJava interface types don't include methods of extended interfaces (issue #64)Loading of jpy DLL fails for user-specific Python installations on Windows (issue #58)Java interface types didn't expose java.lang.Object methods (issue #57)Java 1-arg static method was confused with a zero-arg non-static method (issue #54)Python interpreter crash occurred when executing del statement on Java arrays (issue #52)Python extensions loaded from Java couldn't see Python symbols (Linux) (issue #38)ImprovementsIt is now possible to use jpy Java API to work with multiple Python installations (issue #35).
A tool called 'jpyutil.py' can be used to write configuration files that determine the required shared libraries
for a given Python versions.
A new Java system property 'jpy.config' is used to point to a desired configuration file.Simplified jpy installation (issue #15):removed need to add JVM path to PATH (Windows) / LD_LIBRARY_PATH (Unix) environment variableremoved need to compile Java module using Mavenremoved need to specify JDK_HOME environment variable, if JAVA_HOME already points to a JDKAdded 'jclass' attribute to Python type that wraps a Java class (issue #63) .Java API extensionsnewjpy.org.PyObject.executeCode()methodsnewjpy.org.PyModule.getBuiltins()methodnewjpy.org.PyModule.getMain()methodnewjpy.org.PyModule.extendSysPath()methodJava API configuration changes:System propertyjpy.jpyLib:System propertyjpy.jdlLib:System propertyjpy.pythonLib:System propertyjpy.config:Loaded fromFile./jpyconfig.propertiesResource/jpyconfig.propertiesFile${jpy.config}Python API configuration changes:Loaded fromFile./jpyconfig.pyResource${jpy-module}/jpyconfig.pyAttribute java_homeAttribute jvm_dllPython API extensionsnewjpyutilmodulejpyutil.init_jvm(...)jpyutil.preload_jvm_lib(...)newjpyutiltoolusage:jpyutil.py [-h] [--out OUT] [--java_home JAVA_HOME] [--jvm_dll JVM_DLL]Added basic support for Java Scripting Engine API (issue #53)Other changesSwitched to Apache 2.0 license from version 0.8 and later (issue #60)Version 0.7.5Fixed bad pointer in C-code which caused unpredictable crashes (issue #43)Version 0.7.4Fixed a problem where jpy crashes with unicode arguments (issue #42)Fixed segmentation fault occurring occasionally during installation of jpy (issue #40)Improved Java exception messages on Python errors (issue #39)Version 0.7.3Fixed problem where a Java primitive array argument has occasionally not been initialised by a
related Python buffer argument (issue #37)Version 0.7.2Added backward compatibility with Python 2.7 (issue #34).Added Java parameter annotation 'output' (issue #36).
This is used to optimise passing Python buffer arguments where Java primitive arrays are expected.Removed debugging prints of the form "JNI_OnLoad: ..."Corrected documentation of jpy.array(type, init) function, which was said to be jpy.array(type, length)Removed console dumps that occurred when calling from Java proxies into PythonUpdated Java API documentation and added it to Sphinx doc folder (doc/_static/java-apidoc)Added new diagnostic F_ERR flag to Java class PyLib.DiagJava class PyLib is no longer instantiableVersion 0.7.1Updated README and added MANIFEST.in after recognising that the jpy-0.7.zip distribution misses most of the
required source files and learning what to do on this case.Version 0.7Initial version.