Solved.
MrQuattro build # cat /etc/java-config-2/build/compilers.conf
# If the ebuild supports it
# it will check the COMPILERS var front to back and
# use the fist compiler that is installed
#COMPILERS="ecj-3.1 jikes javac"
COMPILERS="javac"
MrQuattro build # cat /etc/java-config-2/build ...