I meant to blog about this a while back, but the recent deluge of security updates has pushed it to the sidelines. The current HEAD version of IcedTea for building OpenJDK 6 (what will eventually become 1.13) now supports building with HotSpot 23 in preference to the version in the OpenJDK 6 tarball, HotSpot 20. Indeed, this is the default, should you not be building the Zero assembler port. As users of 7 will know, Zero doesn’t work with HotSpot 22 & 23, though signs are good for HotSpot 24, which is currently being tested in the 7 updates forest.

Building OpenJDK 6 with HotSpot 23 was delightfully uneventful in the end, despite earlier warnings from Oracle that they’ve not tested anything beyond 20. We saw no problems during build and a clear run of HotSpot jtreg tests was also a good sign (bar a few JSR292 patches which we’ve since patched out). With luck, things should be good for the 1.13.0 release (which we hope will not take the year that 1.11->1.12 took) and we may even be able to get it upstream into OpenJDK 6 at some point.

Gentoo users can get their hands on this now by using the icedtea-6.9999 ebuild in java-overlay. Other users will need to check out Mercurial repository and build it themselves.

$ /usr/lib/jvm/icedtea-6/bin/java -version
java version "1.6.0_27"
OpenJDK Runtime Environment (IcedTea6 1.13.0pre+re162a16dad26)
(Gentoo build 1.6.0_27-b27)
OpenJDK 64-Bit Server VM (build 23.7-b01, mixed mode)