Difference com.sun.jersey and org.glassfish.jersey
The only difference between com.sun.jersey and org.glassfish.jersey is that the package name was changed because Jersey team is now part of another organization (Glassfish). Versions below 2 use package com.sun.jersey, versions above 2 use org.glassfish.jersey. And yes, there are some differences between 1.x and 2.x.