ClassNotFound but class is there

Question

We have a very strange problem. We have a jar file that contains, among other things, the class ProgressWindow, which has a static method called closeWindow(). This method is called from another class which is in the same jar, from a finally{}. We are running on Solaris. The java program runs essentially as a service which is called from another java program. We find that if the "client" is run on the same box as the "server", all is ok, but if the "client" is run from a different box we get a ClassNotFoundException when calling the static method. We are running out of ideas. Has anyone seen anything similar to this?

Answer 1

Well, whoever needs the class--client, server, or both--has to have a way to access it. For standalone apps (as opposed to applets or servlets) that's general by indicating a directory or jar file on the local file system. You can, however, use a URLClassLoader to get a class from any URL, or any custom classloader you can create to get the class however you want. Regardless though, whoever needs it has to be able to get to it.
If you, say, moved the client to a different machine, and didn't copy the appropriate class files or jar file(s), or put them in a different directory than they were on the server, but didn't change the classpath, that would be one way it could break. Without more details, anything anybody here could suggest would just be speculation.