Python in a Nutshell

Chapter 25. Extending and Embedding Jython

Jython implements Python on a Java Virtual Machine (JVM). Jython’s built-in objects, such as numbers, sequences, dictionaries, and files, are coded in Java. To extend Classic Python with C, you code C modules using the Python C API (as covered in Chapter 24). To extend Jython with Java, you do not have to code Java modules in special ways: every Java package on the Java CLASSPATH (or on Jython’s sys.path) is automatically available to your Jython scripts and Jython interactive sessions for use with the import statement covered in Chapter 7. This applies to Java’s standard libraries, third-party Java libraries you have installed, and Java classes you have coded yourself. You can also extend Java with C using the Java Native Interface (JNI), and such extensions will also be available to Jython code, just as if they had been coded in pure Java rather than in JNI-compliant C.

For details on advanced issues related to interoperation between Java and Jython, I recommend Jython Essentials, by Samuele Pedroni and Noel Rappin (O’Reilly). In this chapter, I offer a brief overview of the simplest interoperation scenarios, which suffices for a large number of practical needs. Importing, using, extending, and implementing Java classes and interfaces in Jython just works in most practical cases of interest. In some cases, however, you need to be aware of issues related to accessibility, type conversions, and overloading, as covered in this chapter. ...