Introduction to Oracle WebLogic Server for OC4J Users 3-3
Figure 3–2 Comparison of Oracle WebLogic Server and OC4J with a Front-End Web
Server
3.1.1.3 OC4J and Oracle WebLogic Server Clustering Features
Oracle Application Server 10g Release 3 10.1.3 introduced the following concepts related to clustering:
■
The Oracle Application Server cluster topology, which enables multiple Oracle Application Server instances to be managed from a single, active Oracle Enterprise
Manager Application Server Control.
From the Cluster Topology page in Application Server Control, you can view the multiple Oracle Application Server instances in the cluster topology and perform
management tasks on those instances. The different instances within the cluster topology communicate via Oracle Notification Service ONS.
■
OC4J Groups , which provides a mechanism for grouping OC4J instances within
the cluster topology and performing group-wide tasks on all the OC4J instances at once.
For example, after you created a group of OC4J instances, you can deploy an application to the group or modify data sources for the group. One key restriction
is that each OC4J within the group must be identical in configuration to the other OC4J instances in the group.
■
OC4J Application Clustering , which is the habilitate to communicate state
information among applications deployed to different OC4J instances within the cluster topology.
For more information about how these OC4J features compare to Oracle WebLogic Server, refer to the following:
■
Table 3–1 compares the OC4J clustering features with those available in Oracle
WebLogic Server.
■
Figure 3–3 illustrates differences between OC4J and Oracle WebLogic Server
clustering.
3-4 Oracle Fusion Middleware Upgrade Guide for Java EE
Figure 3–3 Comparison of OC4J Groups and Oracle WebLogic Server Clusters
3.1.2 Comparing OC4J and Oracle WebLogic Server Directory Structures
The directory structure of a typical Oracle WebLogic Server domain differs from the directory structure of an Oracle Application Server 10g instance in several ways.
When you install Oracle Application Server 10g, you create a single Oracle home that contains the j2ee directory. The OC4J-specific configuration files and log files reside
inside the j2ee directory.
In Oracle WebLogic Server, the installation is enclosed within a Middleware home. Within the Middleware home, the installer creates the Oracle WebLogic Server home
directory. When you configure a domain, the Oracle WebLogic Server Configuration Wizard creates a new domain inside the user_projects directory.
Figure 3–4 shows the difference between the Oracle WebLogic Server and OC4J
directory structures.
Table 3–1 Comparing OC4J Clustering Features with Oracle WebLogic Server
OC4J Feature Oracle WebLogic Server
Equivalent Feature
More Information
Oracle Application Server cluster topology
Oracle WebLogic Server domain
Understanding WebLogic Server Domains in the Oracle
Fusion Middleware Understanding Domain
Configuration for Oracle WebLogic Server
OC4J groups Oracle WebLogic Server
clusters Understanding WebLogic
Server Clustering and Cluster Architectures in
Oracle Fusion Middleware Using Clusters for Oracle
WebLogic Server
OC4J application clustering Oracle WebLogic Server
HTTP Session State Replication
HTTP Session State Replication in Oracle Fusion
Middleware Using Clusters for Oracle WebLogic Server
