I downloaded the stuff from git and launch the command prompt in my project folder and type "gradlew setupDecompWorkspace". And no, i'm not sure that gradle is using the 64-Bit Java.
https://github.com/RewisServer/RewiModhttps://github.com/RewisServer/RewiMod <--- The project i want to work with. I can't remember that i set GRADLE_OPTS or JAVA_OPTS