In his latest post Matthew Weier O'Phinney introduces you to the new init() method in the Zend Framework 2 controllers and how it differs from the one in version 1.

In Zend Framework 1, controller's had an init() method, which was called after the controller was instantiated. The reason for it was to encourage developers not to override the constructor, and thus potentially break some of the functionality (as a number of objects were injected via the constructor). init() was useful for doing additional object initialization. [...] But this feature is missing from ZF2; how can we accomplish this sort of pattern?

In Zend Framework 2, there's no Controller constructor by default anymore, so you have to do things slightly differently. He shows you how to use the event manager to simulate the same thing, attaching an event to the "dispatch" of the controller to do the work. He came back and updated the post with a second method that could do the same thing - using the ServiceManager from inside a module and attaching the event that way.