As part of the OpenJDK project, various organizations have been working on OpenJDK 6, a freely distributable Java 6 implementation based on the open source OpenJDK 7 code base. Most Linux distributions are now shipping OpenJDK 6 binaries.
Soylatte (Java 6 Port for Mac OS X) was originally based on the BSD port of the JRL licensed Java 6 code base, which significantly constrains end-user usage and distribution rights. With Sun's approved re-licensing of the BSD changes for use in OpenJDK 7, a backport to OpenJDK 6 was made possible.
I've added support for OpenJDK 6 on Mac OS X, based on Brian Gardner's work backporting the OpenJDK 7 BSD changes to OpenJDK6/FreeBSD. Unlike the legacy Soylatte builds, OpenJDK 6 is:
The initial beta release is available for testing via the MacPorts openjdk6 port (Leopard only), or as a binary from the Soylatte web page (Leopard/Tiger, untested on Tiger). My ability to provide 10.4 support is constrained without access to a 10.4 machine, and any testing/development assistance is most welcome.