Rather than using a command interpreter or dispatch table, commands within a messaging system are given a name which matches the filename for the class file implementing the command. A command name, or command number, may be subsequently passed to a server in a messaging system and used to dynamically load and instantiate a message command by loading a class of the same name. Additional command classes may therefore be added or deleted, at runtime, from client or server code without halting the application. An error condition is signaled when the command name is unrecognized, when the command code is unavailable or when there are problems instantiating an instance of the command class. Once the class code is loaded, a new instance of the class is created and the command object may be utilized.