title: Hazelcast: use ConcurrentHashMap or ITopic messaging object to distribute data?
body: <p>I have an app distributed in multiple tomcats and using a hazel cast to share data. In the app, I use map that needs to be consistent throughout all the Tomcats. Is there any reason why one should prefer using the message distribution mechanism (ITopic object) to keep consistency when the data in the map changes? Or is the distributed ConcurrentHashMap always the right choice in the described case – when I need the maps in each tomcat to hold the exact same data at all times (operation speed, reliability)?
  How does ConcurrentHashMap work under the hood to keep fully consistent in different JVMs? And, on the under hand, how does distribute message work? </p>