Last time I checked (RM 5.2) RapidMiner 5.2 was not compiling with Java 7 (as I remember a JDBC driver interface was extended in Java, but the old was implemented in RM). The official plan that the Java 6 EOL seems to be Feb 2013 (http://www.oracle.com/technetwork/java/eol-135779.html), before Java 8. So I think the next target will be Java 7. Do you have an estimate when will this is going to happen?
Thanks, gabor