Homebrew/homebrew — pull request #30798 by kensipe (2014-07-10 18:25:23+00:00)
Title: Mesos Requires Maven to Use Java 7+ (2)

revious check was invalid. It is possible for java 8 to be installed without java 7 and the build will work (but this formula fails). It is also possible for java 7 to be installed (passing this check), but mvn is configured to use java 6. The correct check is to verify what java version mvn is using.