Message Broker - The message-oriented middleware server that hosts messaging destinations (i.e., queues and topics) for the purposes of asynchronous communication. Sometimes known as a queue manager
Message Queue - A messaging destination that uses a
queue data structure to hold messages and is hosted by the message broker. The alternative to a queue is a topic which provides publish/subscribe semantics.
Resource Adapter - A
Java EE Resource Adapter is a component that allows communication between a
Java EE application and an enterprise information system such as a database server, a messaging server, a CRM server, an ERP server, etc.
More information about JMS and related concepts can be found in the
The Java Message Service API.
Hope that helps.
Bruce