Adding to the classpath on OSX
If you want to make a certain set of JAR files (or .class files) available to every Java application on the machine, then your best bet is to add those files to /Library/Java/Extensions
.
Or, if you want to do it for every Java application, but only when your Mac OS X account runs them, then use ~/Library/Java/Extensions
instead.
EDIT: If you want to do this only for a particular application, as Thorbjørn asked, then you will need to tell us more about how the application is packaged.
In OSX, you can set the classpath from scratch like this:
export CLASSPATH=/path/to/some.jar:/path/to/some/other.jar
Or you can add to the existing classpath like this:
export CLASSPATH=$CLASSPATH:/path/to/some.jar:/path/to/some/other.jar
This is answering your exact question, I'm not saying it's the right or wrong thing to do; I'll leave that for others to comment upon.