For HTTP based request, within the application server environment, the Oracle HTTP Server (OHS) acts as a front-end listener and OC4J as the back-end J2EE application server.
For RMI-based requests —such as EJB and JMS—clients should send their requests directly to OC4J.
A browser accesses the OHS listener for all HTTP requests. The Oracle HTTP Server is an Apache server.
The request flow between Oracle HTTP Server and OC4J is as follows:
- incoming HTTP request is received by the Oracle HTTP Server listener.
- HTTP Server passes the request to an OC4J instance through the mod_oc4j module.
The connection between Oracle HTTP Server and OC4J uses the Apache JServe Protocol (AJP) on a port number negotiated during OC4J startup.
HTTP Application Listener request flow
AJP is faster than HTTP, through the use of binary formats and efficient processing of message headers.