The build process currently uses apt, the annotation processing tool, to process @SysCallTemplate annotations. apt is deprecated in Java 7. It is replaced
by javac and the Java 6 APIs javax.annotation.prcessing and javax.lang.model .
This was discussed on the mailing list and it was decided that annotations should be processed via the Java 6 API. Consequently, the Jikes RVM will require a Java 6 JDK instead of a Java 5 JDK to build.