Java 7 on ppc64 never worked very well for us. We have Java 8 now.
Package-Manager: portage-2.2.28
DESCRIPTION="Virtual for Java Runtime Environment (JRE)"
SLOT="1.7"
-KEYWORDS="~amd64 ~arm ~ppc64 ~x86 ~amd64-linux ~x86-linux ~ppc-macos ~x64-macos ~x86-macos ~sparc-solaris ~sparc64-solaris ~x64-solaris ~x86-solaris"
+KEYWORDS="amd64 ~arm x86 ~amd64-linux ~x86-linux ~ppc-macos ~x64-macos ~x86-macos ~sparc-solaris ~sparc64-solaris ~x64-solaris ~x86-solaris"
RDEPEND="|| (
virtual/jdk:1.7