Sorry I do not understand -- you suggest pushing Java 7 commits to master and ignoring the error mails on every commit?
PS: Which emails are you referring to here? The *commit* builder for master is on Java 7 only - there is no Java 6 builder for that.
The Java PR builder shouldn't be sending any emails (at any rate, I can't see any notifications configured for it in DEV@cloud) and should only be adding comments to the PR. The suggestion is to ignore those for PRs against master.
ap