This example shows one way to incorporate a Jython class into a Java program. To do this you should follow the following steps: Note: path names are given for a Unix machine. Make the obvious translation for Windows. 1. run "jython Graph.py" in this directory This is just to make sure the Jython code works on your machine 2. run "jythonc --package pygraph Graph.py" in this directory This should produce the Java class pygraph.Graph. Because this is only a shallow freeze of the code in Graph.py, you can modify the actual Python code (and any libraries it depends on) without needed to perform the freeze process again. You will need to repeat this freeze process any time you add new methods to the Graph class that override Java methods in its superclass. Notice the strange "@sig ..." doc comments on the __init__ and the setExpression methods. These cause convenient methods to be created on the Java proxy class. 3. run "javac pygraph/PythonGraph.java" You must have both the current directory ('.') and the Jython library directory (\jython.jar) in your CLASSPATH for this to work. 4. run "java pygraph.PythonGraph" You need the same classpath as given above