L2J Server

I use in eclipse git>clone> https://github.com/L2J/L2J_Server.git and same for https://github.com/L2J/L2J_DataPack.git according to the new Zoey76's guides.Installed java8 and use Jre8 in eclipse.
Now when I try to build>ant for datapack,everything is allright.Build succesfull.I get errors with L2j_server and build failed.
[javac] javac: invalid target release: 1.8
[javac] Usage: javac <options> <source files>
BUILD FAILED
Any ideas and as far as Im new here,I'd like some kind of detailed answers if you please.Thanks.

Im not to old to learn...
Have just set JAVA_HOME environment variable to point to the JDK8 installation directory.That solved the problem.

I'll add it to the guide, still working on the web.