By default, directories are stored in the job cache, and .jar files are stored in the shared cache. The .jar files are generally production-time entities (versioned and change less frequently), whereas directories are development entities (not versioned and change more frequently). If the .jar files are not versioned, this mechanism still works, as the cache entities are keyed by both .jar name and checksum. This method lets you store two different .jar files with the same name in the cache without variance.

If the client needs more control over class path and class behavior, you can use settings in the classpathSpecifier object described in Engine Configuration Settings.