Configuring the Client

Before you can access an enterprise bean from a client, you must consider the following:

• Configuring the Client Classpath for OC4J

• Selecting an Initial Context Factory Class

• Specifying Security Credentials

• Selecting an EJB Reference

Configuring the Client Classpath for OC4J

Table 29-1 lists the OC4J-specific JAR files that you must install on the client depending on what your client looks up. The Source column indicates from where you get a copy of the required JAR from <OC4J_HOME>.

Only the oc4jclient.jar should be on the client classpath. All other JAR files required by the client are referenced in the oc4jclient.jar manifest classpath.

Table 29-1 OC4J Client Classpath Requirements

OC4J JAR	Source (Relative to <OC4J_HOME>)	EJB Lookup	JMS Connector Lookup	OEMS JMS Lookup	OEMS JMS Database Lookup
adminclient.jar	/j2ee/<instance>/lib
bcel.jar	/j2ee/<instance>/lib
connector.jar	/j2ee/<instance>/lib
dms.jar	/j2ee/<instance>/lib
ejb.jar	/j2ee/<instance>/lib
javax77.jar	/j2ee/<instance>/lib
jazncore.jar	/j2ee/<instance>
jdbc.jar	/j2ee/<instance>/../../lib
jms.jar	/j2ee/<instance>/lib
jmxri.jar	/j2ee/<instance>/lib
jndi.jar	/j2ee/<instance>/lib
jta.jar	/j2ee/<instance>/lib
oc4j.jar	/j2ee/<instance>
oc4jclient.jar	/j2ee/<instance>
oc4j-internal.jar	/j2ee/<instance>/lib
ojdbc14dms.jar	/j2ee/<instance>/../../oracle/jdbc/lib
optic.jarFoot 1	/opmn/lib

^Footnote 1 Required only if you plan to use the opmn:ormi prefix in JNDI look up with Context.PROVIDER_URL (see "Configuring an Oracle Initial Context Factory").

If you download any of these JAR files into a browser, you must grant certain permissions (see "Granting Permissions in Browser").

Selecting an Initial Context Factory Class

You use an initial context factory to obtain an initial context–a reference to the JNDI namespace. Using the initial context, you can use the JNDI API to look up an enterprise bean, resource manager connection factory, environment variable, or other JNDI-accessible object. The type of initial context factory you use depends on your client type and how you are using OC4J: standalone, or as part of Oracle Application Server (see "Configuring the Initial Context Factory").

Specifying Security Credentials

If the client and target enterprise bean are not collocated, not deployed in the same application, and the target EJB application is not the client's parent, then your client must specify its credentials before accessing the target enterprise bean (see "Specifying Credentials in EJB Clients").

Selecting an EJB Reference

In EJB 3.0, to access an EJB 3.0 enterprise bean or resource in an EJB client, you can use annotations, resource injection, and default JNDI names (based on class and interface names) instead of doing a JNDI lookup with a predefined environment references.

In EJB 2.1 or in EJB 3.0 (for standalone Java clients), to access an enterprise bean or resource, you must do a JNDI lookup on a predefined environment references (see "Configuring Environment References"). To access an EJB 2.1 enterprise bean or resource, choose the appropriate predefined environment reference (actual or logical; local or remote) and look it up using a JNDI initial context (see "Selecting an Initial Context Factory Class").

If you access an enterprise bean by reference from within your client implementation, perform a JNDI lookup using the <ejb-ref-name> defined in the EJB deployment descriptor. For more information on defining an EJB reference to a target enterprise bean, see "EJB Environment References".

Table 29-2 shows when to prefix the reference with java:comp/env/ejb/, which is where the container places the EJB references defined in the deployment descriptor.

Table 29-2 When to Use the java:comp/env/ejb/ Prefix

Client	Initial Context Factory	Use Prefix?
EJB Client	Default RMIInitialContext	Optional Not Used
Standalone Java Client	Default ApplicationClientInitialContext	Optional Mandatory
Servlet or JSP Client	Default RMIInitialContext	Optional Not Used

Example 29-1 shows how to look up an enterprise bean with logical name ejb/HelloWorld using the java:comp/env/ejb/ prefix, and Example 29-2 shows how to look up this enterprise bean without the prefix.

Example 29-1 Looking Up an Enterprise Bean With the Prefix

InitialContext ic = new InitialContext();
HelloHome hh = (HelloHome)ic.lookup("java:comp/env/ejb/HelloWorld");

Example 29-2 Looking Up an Enterprise Bean Without the Prefix

InitialContext ic = new InitialContext();
HelloHome hh = (HelloHome)ic.lookup("ejb/HelloWorld");