Gotcha, so you have JDK 8 and want to upgrade the gameserver so it supports it?
Here's how I'd do it:
- Update the build scripts(pom.xml or build.xml) to support 1.8.
- Attempt to compile the gameserver, see what breaks.
- Modify the code to support the new version.
I'd recommend trying this with the loginserver first as the code is smaller(still bloated, but smaller than the gameserver)
EDIT: This question hurts my brain, do you want to downgrade or upgrade the gameserver? Running JDK 7 will be fine for building the gameserver if the build.xml or pom.xml require 1.7, if you are wanting to build using a newer JDK, follow my steps explained above.