As I understand it, as of “Java for Mac OS X 10.6 Update 3”, there are 3 places you will find Java installed on MacOS.
- /System/Library/Frameworks/JavaVM.framework/ was the old place.
- /System/Library/Java/JavaVirtualMachines/ is the new standard place – there you will find the new release.
- /Library/Java/JavaVirtualMachines is for ‘…developer previews, and 3rd party JVMs’
Note the MacOS rule of putting Apple-supplied standard components in /System/Library and local extensions into /Library
The JDK installed by default does not now have a src.jar (although it is a JDK, so has javac etc). But if you install the ‘Java Developer package’ from Apple, you will get
/Library/Java/JavaVirtualMachines/1.6.0_22-b04-307.jdk
which has src.jar under Contents/Home
So I think that the sane thing to do is install the developer package and point to it from your IDE.
Update – for “Java for Mac OS X 10.7 Update 1”, having installed the developer package the source can be found at
/Library/Java/JavaVirtualMachines/1.6.0_29-b11-402.jdk/Contents/Home/src.jar