Using JNDI

JNDI is a standard component of JDK 1.3 and is, therefore, also part of J2EE 1.3. JNDI is also included in J2EE 1.2 and is available as a standard Java extension for JDK 1.2 and earlier.

While developing code, the program's CLASSPATH must include the location of the JNDI class libraries. As long as the JAVA_HOME environment variable has been set up, the JNDI classes will be available to the Java compiler.

Running a JNDI-aware program requires a JNDI service to be running and the classes for that service to be available to the program. Typically, this requires the CLASSPATH to include one or more JAR files provided by the JNDI provider or a J2EE server vendor. For implementation-specific details, see the vendor's documentation.

By default, running a J2EE server starts a naming service on the same machine. If the default behavior isn't required, you must change the J2EE server configuration to use an existing JNDI server.

Using Sun Microsystems' J2EE Reference Implementation

Using JNDI with Sun Microsystems' J2EE Reference Implementation (RI) is straightforward. Ensure that

• The J2EE_HOME variable exists

• The CLASSPATH variable includes the j2ee.jar file from the lib directory of the J2EE home directory

Examples of how to do this both for Windows and for Unix are shown in this section.

J2EE RI for Windows

Under systems running Microsoft Windows NT or 2000, you can set the class path interactively with the following:

Set CLASSPATH=%J2EE_HOME%libj2ee.jar;%CLASSPATH%

Typically, it is better to set the class path as a system-wide environment variable (via the My Computer properties dialog). A suitable value is as follows:

.;%J2EE_HOME%libj2ee.jar

The class path can also include additional JAR files and directories for other Java components.

It is important to define the current directory (.) in the class path; otherwise, the Java compiler and runtime systems will not find the classes for the program being developed.

J2EE RI for Linux and Unix

Under Linux and Unix, set the class path with the following:

CLASSPATH=$J2EE_HOME/lib/j2ee.jar:$CLASSPATH

Starting the JNDI Server

Startup the J2EE RI server, as Day 2, “The J2EE Platform and Roles,” described, and the JNDI server will start at the same time. You start the J2EE server by entering the following command from a command-line window:

j2ee –verbose

The J2EE server will run in that window until you close the window down or enter the following shutdown command from another command-line window:

j2ee -stop