The GNU Project has released version 4.0.1 of GCC, the GNU Compiler Collection. GCC contains frontends for C, C++, Objective C, Chill, Fortran, Ada, and Java as well as libraries for these languages. GCC's Java is a clean room implementation that doesn't use any Sun code, so it doesn't always exactly match Sun release versions, but this is roughly at the Java 1.4 level with some omissions. Verson 4.0.1 primarily fixes regressions in GCC 4.0.0 relative to previous releases.
Apple has posted a beta of Java 1.4.2 release 2 on the Apple Developer Connection (registration and Mac OS X 10.4 required). This beta will overwrite the existing Java 1.4.x installation, and is not easily uninstallable so be careful. This beta fixes a couple of dozen assorted bugs.