org.eclipse.core.commands
Interfaces 
ICategoryListener
ICommandListener
ICommandManagerListener
IExecutionListener
IHandler
IHandlerAttributes
IHandlerListener
IParameter
IParameterValues
Classes 
AbstractHandler
Category
CategoryEvent
Command
CommandEvent
CommandManager
CommandManagerEvent
ExecutionEvent
HandlerEvent
Parameterization
ParameterizedCommand
Exceptions 
ExecutionException
NotHandledException
ParameterValuesException