JDK Source Code on MacOSX

After installing the latest update of Java for MacOSX Snow Leopard - must have been in March 2010 if my file system is not cheating on me - I missed the source code for the JDK classes. I remembered I had to install the Java Developer Package from the Apple developer center, but I couldn't find any. Consequently, I learned to live without the sources and forgot about the issue.

Yesterday I stumbled across a big performance issue in the upcoming Xtend2 compiler that only happened on my machine. Profiling yielded that it was because I have no local sources (another strange story).

So I decided to look for the developer package once again et voilà: Apple had been so kind to release it in the meantime. BTW, the timestamp says October 20th :-o

So here's what I did to get the MacOSX Java sources back (it's on your own risk, I disclaim any responsibility if you should break or machine)

1) Get an Apple Developper Connection account (it's free, but you have to register).
2) Login choose Java and download the Java for Mac OS X Developer Package matching your OS and Java version.
3) Install the DMG.

The install location of the JDK is somehow weird - e.g. you cannot directly open it in Eclipse's "Choose JDK location" dialog. To make it the default, I found it easiest to retarget the symbolic link pointing to the default JRE. You have to be super user in this case.

4) Open a Terminal and enter

cd /System/Library/Frameworks/JavaVM.framework/Versions
sudo rm CurrentJDK
sudo ln -s /Library/Java/JavaVirtualMachines/1.6.0_22-b04-307.jdk/Contents CurrentJDK

If Eclipse uses the default MacOSX JDK, you should now have sources.