Included in the distribution is a class called XMLExecutable which uses XML classes from the com.sun.xml, org.xml.sax and org.w3c.dom packages.
These are not included with the Simkin distribution. You can download them from Javasoft directly from here.
The classes (XMLElementObject and XMLExecutable) can be reimplemented to use a different XML library, without affecting the rest of the interpreter.
In all cases you will need to add the Simkin.jar file to your classpath when building your application.
If you are building your own JAR files, you may find it more convenient to unpack the classes in Simkin.jar. Find a suitable directory to store them, and use the command
jar -xvf Simkin.jarto unpack the class files.
Simkin classes occupy the following packages: