Java 8 released and the actual Eclipse version doesn’t support it out of the box. I found an official patch that adds this support to the actual version of Kepler SR2. Here is the update site:
http://download.eclipse.org/eclipse/updates/4.3-P-builds
Here the official JDT page that led me to this page: https://wiki.eclipse.org/JDT/Eclipse_Java_8_Support_%28BETA%29
Be sure to read the instructions as this patch is for Eclipse 4.3.2 only and is not intended to be used with other versions.
There is still a problem that there faceted projects doesn’t support 1.8 yet. I’ll update this post as soon as I find a working solution for 4.3.2. If there is no update I changed to 4.4 build ;-)
EDIT: Also no success with Luna (4.4) M6