NoClassDefFoundError org/xml/sax/InputSource

Hello,

I've written a Java program that exposes a class that when constructed
creates a Spring context, and then makes some remote calls using
Spring's HTTPInvoker class.

I've had success with this Java program by calling a main method (for
testing only) from both QSH and on the iSeries command line via the
JAVA command.

I created a module that wraps my Java class, and have created a very
simple RPG program that should call the main method (for testing
again), however when calling the main method from inside an RPG
program, a Java NoClassDefFound exception is thrown for
org.xml.sax.InputSource, and surfaces as message RNQ0301.

The InputSource class should be part of the JRE, and judging by the
fact that I can call my class from QSH and the iSeries command line, I
am lead to believe that this class is indeed present, but somehow not
visible from my RPG module.

Could anyone give me any ideas as to why this class would not be
visible to the classpath when the Java program is called from within
an RPG module? It makes me wonder if there are different JVM's being
used. But when checking from QSH and JAVA *VERSION, the version
returned is 1.4.2.

Thanks,
Joe