Py4J

Methods are called as if the Java objects resided in the Python interpreter.

All Java collections can be accessed using the standard Python collection methods.

There is no code to generate and no interface to implement for shared objects on both sides, because Py4J runs as a daemon.

What is new in this release:

• Ability to fail early if the py4j.java_gateway.JavaGateway cannot connect to the JVM.
• Added support for long primitives, BigDecimal, enum types, and inner classes on the Java side.
• Set saner log levels
• Many small bug fixes and API enhancements (backward compatible).
• Wrote a section in the FAQ about security concerns and precautions with Py4J.
• Added support of Travis-CI and cleaned up the test suite to remove hardcoded paths.

What is new in version 0.5:

• Added the ability to import packages (e.g., java_import(gateway.jvm, 'java.io.*'))
• Added support for pattern filtering in JavaGateway.help() (e.g., gateway.help(obj,'get*Foo*Bar'))
• Added support for automatic conversion of Python collections (list, set, dictionary) to Java collections. User JavaGateway(auto_convert=True) or an explicit convertor.
• Created two Eclipse features: one embeds the Py4J Java library. The other provides a default GatewayServer that is started when Eclipse starts. Both features are available on the new Py4J Eclipse update site: http://py4j.sourceforge.net/py4j_eclipse
• Redesigned the module decomposition of Py4J: there are no more mandatory circular dependencies among modules.

What is new in version 0.2:

• It is now possible to call constructors and reference static members: use the jvm member of a JavaGateway object.
• Java Map is converted to a Python Dictionary.
• Field access is supported through the get_field function or the auto_field=True member of JavaGateway.
• Obtain an interactive help page with JavaGateway.help(object).
• Set is only accessible through the Java Set interface for now.
• Arrays can be referenced, but individual items can only be accessed with this workaround: gateway.jvm.java.lang.reflect.Array.get(object,index).
• Complete rewrite of the reflection engine on the Java side for more flexibility.
• Improved memory model: no more memory leak caused by Py4J.
• New concurrency model: Py4J is now thread-safe.