Discussion Line][Age Eclipse Issue

Hello Guys i have one compile pack L2jFrozen and i would like to know how can i use a java code on it as i read on some other topics this cant be posible so i find l2jfrozen SVN (  http://subversion.assembla.com/svn/L2jFrozenInterlude/trunk/  ) i add it on SVN repositories on eclipse but when checkout finished and i open the files to put the codes that i need then to comple the pack and take the files i add and to put it in to my pack.... i reallize i didnt had the Java folder is it normal i did somethink mistake or what happent?? and can i  put some java codes on my compile pack??? thnx for your time if you can help help plz :D