Are there any plans to move the Metrics project to Java 7?

If there are, we should bump this to version 2.9 before merging. Otherwise we'll have to stick with Jersey 2.6 which was the last release working with Java 6 (see [Migrating from Jersey 2.6 to 2.7](https://jersey.java.net/documentation/latest/migration.html#mig-2.7)).