Programming WebLogic RMI
RMI communications in WebLogic Server use the T3 protocol, an optimized protocol used to transport data between WebLogic Server and other Java programs, including clients and other WebLogic Servers. A server instance keeps track of each Java Virtual Machine (JVM) with which it connects, and creates a single T3 connection to carry all traffic for a JVM.
For example, if a Java client accesses an enterprise bean and a JDBC connection pool on WebLogic Server, a single network connection is established between the WebLogic Server JVM and the client JVM. The EJB and JDBC services can be written as if they had sole use of a dedicated network connection because the T3 protocol invisibly multiplexes packets on the single connection.
Any two Java programs with a valid T3 connection—such as two server instances, or a server instance and a Java client—use periodic point-to-point "heartbeats" to announce and determine continued availability. Each end point periodically issues a heartbeat to the peer, and similarly, determines that the peer is still available based on continued receipt of heartbeats from the peer.