This section takes a high-level look at each service provided by OC4J to servlets and EJBs. Some of these are standard J2EE services while others are Oracle value-added services. The OC4J services consist of the following:
Java Naming and Directory Interface (JNDI)
J2EE Connector Architecture
Java DataBase Connectivity (JDBC)
Java Message Service (JMS)
Remote Method Invocation (RMI)
Java Transaction API (JTA)
Java Authentication and Authorization Service (JAAS)
Java API for XML Parsing (JAXP)
Java Object Cache
We’ll discuss JNDI first because it is often used to access other resources in the list.
The Java Naming and Directory Interface provides Java programs with standardized access to various naming and directory implementations. Within OC4J, servlets and EJBs can access global resources, such as Data Sources, and environment variables defined in each servlet or EJB deployment descriptor with the default JNDI context. The OC4J’s naming mechanism is implemented using an XML file.
If a servlet or EJB requires access to an external directory, such as LDAP implemented by the Oracle Internet Directory, the URI to the external directory can be specified as a parameter in the servlet or EJB’s deployment descriptor, looked up via JNDI using the default context, and then used to create a new context that accesses the external directory once again using JNDI.
JNDI can access various naming and directory services using service ...