Ubuntu and Java
You get kind of used to hearing OSX people complaining about not having the latest Java environment but I always thought that Linux was one of the operating systems blessed by Sun (along with Windows and Solaris).
The odd thing is that I couldn't use apt-get to install a working Java environment from Sun on Feisty or Dapper Drake. Amazingly it just SIGSEGV'd with no hint of what happened - probably a libc problem. Using strace didn't help either. I tried installing X11, fonts and a bunch of other things it might have possibly needed but it still couldn't manage a sensible error message. It looks like it's a common enough problem too although it doesn't appear to be in Sun's bug database .
I manually installed Java 1.5 and it works fine - a manual install of 1.6 SIGSEGV'd too.
After all that I thought I'd have a look at the OpenJDK - the GPLed future of the JDK. The svn repository only seems to have documentation without any source - you have to download a tarball of the source to build it. Looks like there is some way to go to making it easy to take contributions from the community.
Sun expect you to share copyright and transfer other rights to them if you want to contribute to the OpenJDK - you sign a form and fax it to them. This seems like a new departure for free software - Linus never made you share copyright and that's one reason why people are more confident about contributing to Linux. The OpenJDK needs to build a community or it may just as well have remained proprietary. It is possible given all the hype around the OpenJDK that it may just turn out to be a footnote in the encouraging rise of the Apache Harmony - Open Source Java SE.
UPDATE: As robilad pointed out in a comment you have to use
https://openjdk.dev.java.net/svn/openjdk/trunkSo it is possible to checkout the OpenJDK from svn - the directory structure is perhaps to discourage the foolhardy :)