Types of Communication Middleware

1.  Message oriented middleware (MOM)

An application component can effectively send a request to another application by doing a local procedure call, which result in the request being package as a message and sent to the calle. The result will be sending back and returned to the application as the result of the procedure call. The calle need to be up and running at the time of communication. They need to know exactly how to refer to each other.

2.  Remote method invocations (RMI)

RMI is essentially the same as RPC, except that it operates on objects instead of application. As the popularity of object technology increased, techniques were developed to allow calls to remote objects. The caller need to be up and running at the time of communication. They need to know exactly how to refer to each other.

3.  Remote procedure calls (RPC)

The application simply send message to logical contact points, often described by means of a subject. The application can indicate their interest for a specific type of message, after which the communication middleware will take care that those messages are delivered to those application.