Today I upgraded to Android SDK 2.3 and I also upgraded the Eclipse Plugin Androi Developer Tools 8.0 (from 0.9.9). I also upgraded my Java Development Kit to 1.6_22.
No
In my case, The JRE went missing (disapear from Eclipse option).
All I did to fix this is re-add the JRE under Windows -> Preferences -> Java -> Installed JREs.
mine was located at /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home