IANAL (I am not a lawyer) but I suggest you read the licensing agreement from Sun about the use of their Java (tm) Technology products! What you are doing is specifically prohibited! You are creating a "custom" distribution, and this is basically what MS tried to do with their "dirty" java and that's why Sun sued them.
Besides that little fact,
you should be aware of a few things:
1) jar files = gzip archives
2) gzip archives use LZW compression, and one of the results of this is that in order to sequentially access any element of the archive,
the entire archive must be uncompressed first. Think about that for a moment.
Not *every* class in rt.jar needs to be loaded during the execution of your java app, and the system class loader loads classes as needed. If it needs to load a class file from rt.jar and it's compressed, the entire file must first be uncompressed in order for the Class file to be located and loaded.
That's why you should NOT compress your jar files, unless you're using them for an
applet. That's really the only valid use of compressing jar files (or other network distributed uses where bandwith is limited). If you're including your own libraries in jar files for an app you are distributing say via a CD-ROM, you still won't compress the Jar files. If you are using an installer, the *entire* installation package might be compressed but the individual jar files themselves should not be.
I hope this clears things up for you.
[ July 23, 2002: Message edited by: Rob Ross ]