Thank you. Your comments encouraged me to take a fresh look at things, and I realize now I was confusing the jar file and the command to start the app. Saxon works. I'm working throught the classpath complexities, too, as there seem to be several places to store classpath information. I'm not sure I wish to modify the .plist file yet.

the classpath is actually fairly easy to understand albeit very verbose. :) some people like to maintain a global CLASSPATH variable in their environment, but i don't like that approach since you tend to lose sight of the dependencies between your programs and their libraries.

the approach i like (and i think most java apps take), is to use the -classpath parameter to the java application. the classpaths can get *very* long, but you have precise control over what is going on. for instance, one application can use one XML library and another use a separate XML library without clashes.

my recommendation is to make heavy use of -classpath (or let MRJAppBuilder do it for you) rather than using other means.