The class hierarchy for the command listeners is:
com.essbase.eas.framework.server.application.AbstractCommandListener com.essbase.eas.server.AppManCommandListener com.essbase.eas.essbase.server.EssbaseCommandListener
All three of these classes are declared as abstract. You must extend from one of these three classes in order to have the framework find your command listener.
The AbstractCommandListener class provides the basic functionality that is needed for the framework. Most of the methods in this class are either final or protected; for most practical purposes, implementers of derived classes should not override the protected methods of this class. For a description of those methods that can be useful to implement in a derived class, see the section Which Methods to Override.
The AppManCommandListener class adds some small functionality to the AbstractCommandListener, mostly dealing with EAS servlet session validation and exception handling during command routing.
The EssbaseCommandListener class adds some Essbase-specific functionality, primarily Oracle Essbase session validation.