Boot JDK requirements for 8 ?

[David Holmes]

This is a build-infra build using profiles forest but I think is a 
general issue :)

I use a JDK 7 as a boot JDK. I've noticed that now javac produces 
version 52 classes files the build produces lots of these "warnings"

Generating headers for jdk base classes
Compiling 1 files for BUILD_ALTCLASSES_JAR
/java/embedded/users/dh198349/profiles/builds/b66/se-linux-i586-ea/jdk/classes/java/lang/Integer.class: 
major version 52 is newer than 51, the highest major version supported 
by this compiler.
   It is recommended that the compiler be upgraded.

I'm not sure exactly where this comes from.

David