Q: Is the Java Message Service another mail API? A: No. The term messaging is broadly defined in computing. It is used for describing various operating system concepts; it is used to describe email and fax systems; and with the JMS API, it is used to describe asynchronous communication between enterprise applications.
JMS messages are asynchronous requests, reports, or events that are consumed by enterprise applications, not humans. They contain vital information needed to coordinate these systems. They contain precisely formatted data that describe specific business actions. Through the exchange of these messages, each application tracks the progress of the enterprise. --------------------- In other words, JMS is for sending messages between application components, and the Java Mail API is for sending an actual email.