Java ebuilds using EAPI<3 will not be correctly prefixified.
We will deal with that by bumping EAPI per package.
# Make sure we use java-config-2
export WANT_JAVA_CONFIG="2"
-# Prefix variables is only available for EAPI>=3
-!use prefix && has "${EAPI:-0}" 0 1 2 && ED="${D}" EPREFIX= EROOT="${ROOT}"
+# Prefix variables are only available for EAPI>=3
+has "${EAPI:-0}" 0 1 2 && ED="${D}" EPREFIX= EROOT="${ROOT}"
# @VARIABLE: JAVA_PKG_PORTAGE_DEP
# @INTERNAL