The Java Kernel engineering team has requested Sun legal clearance to use 7-Zip (http://www.7-zip.org) as the mechanism for bundle compression to reduce download overhead.
This RFE is to prototype and test use of 7-Zip and then integrate use of its binaries for compressing and uncompressing bundles after legal approval is received. The size of the 7-Zip .dll file(s) needed for decompression is still being determined, but the overall savings for a typical bundle collection is expected to be significant.

The tradeoff of benefit vs overhead and complication with using the 7-Zip binaries make this approach painful. A second approach (requiring separate legal approval) using the 7-Zip SDK (but only modifying one of it's "public domain" files, not any under LGPL) is being prototyped.

Also, compression of the Java Kernel .msi file is a much better alternative to the current Microsoft (internal cab file) compression used now. So this RFE and the prototype work has been extended to cover the JK .msi file as well as bundle files.