4. The method of claim 1 , wherein the platform is specific to a hardware and operating system platform.
1. A method of managing internal cluster communications in a cluster of application server instances, comprising: executing a plurality of work processes in the application server instances; establishing internal connections for internal cluster communication between a message server and each of the plurality of work processes executing in the application server instances, wherein internal cluster communication comprises internal communications relating to at least one of events occurring in the cluster and an exchange of messages between work processes executing in the application server instances, the internal connections separate from connections for external cluster communication; providing a message service for the internal cluster communication, the internal cluster communication including inter-application server instance communication via the message server in accordance with a connection-based message passing protocol in which an internal connection established in the message server receives a notification message for each event occurring in the cluster and sends acknowledgement messages to internal connections established in the application server instances responsive to receiving messages being exchanged between work processes executing in the application server instances, the message server being shared by the application server instances through the established internal connections for internal cluster communication between the message server and each of the plurality of work processes executing in the application server instances; operating a cluster manager to manage the internal cluster communication in accordance with the connection-based message passing protocol, the internal cluster communication sent over the established internal connections for internal cluster communications between the message server and each of the plurality of work processes executing in the application server instances, the cluster manager: communicating an event in the cluster to the message server using an event handler, the event handler sending a notification message of the event to the message server; relaying the notification message of the event in the cluster to one or more of the application server instances using a notification handler, the notification handler causing a function to be performed in one or more of the application server instances responsive to receiving the notification message; and communicating messages to be exchanged between work processes executing in the application server instances to and from the message server using a message server communication handler, the message server communication handler: acknowledging receipt of messages received from the work processes; and relaying messages received from an originating work process to a destination work process, including replicating a multicast message received from the originating work process for broadcast to all other work processes executing in the application server instances.