OC4J is the Oracle Application Server (Oracle Container 4 Java, formerly Orion), up to Oracle 10g.
Oracle Corporation refers to its implementation of the Java EE specification as Oracle Containers for J2EE and abbreviates the concept as OC4J. OC4J, originally based on the IronFlare Orion Application Server, has developed solely under Oracle's control since Oracle Corporation acquired the source code.
OC4J includes the following servers:
- Web Container
- Enterprise JavaBean Container
- JMS Server
Since the BEA purchase by Oracle, it has been replaced in 11g by WebLogic.