Day 9. Writing Enterprise Applications with JNDI

Yesterday, you covered the advanced concepts of the Java Database Connectivity (JDBC) 2.0 API, including scrollable result sets, batch updates, RowSets, and so on. You completed your study of the advanced concepts by extending the online bookshop and adding JDBC functionality to keep and retrieve data stored in the PointBase evaluation database.

The next set of enterprise technologies supported by WebLogic Server that you will be studying this week and next week are Enterprise JavaBeans (EJBs). Enterprise JavaBeans are a common, consistent way to build server-side components. Because the EJB components reside on the server side, they need to promote and publicize the functionality that they provide to the outside world to enable reuse and sharing of that functionality.

Today you will be studying how server-side components such as EJB components can advertise their services to different client applications and how client applications can locate and use the services provided by the server-side components. This mechanism that enables client applications to locate server-side components is called a naming service. Directory service is an extension of the naming service.

Naming and directory services have evolved over the years. Server-side components use different and disparate naming and directory services to share their functionality. This means that a client application that requires server-side components registered with different naming services has to include proprietary code for each naming service. The Java Naming and Directory Interface (JNDI) attempts to unify disparate naming and directory services using a common and consistent API called the JNDI API.

The JNDI API is integral to using and accessing database connections, message queues, EJBs, and so on. On later days you will always use the JNDI API as the first step before using the enterprise resources. Hence, you need to get acquainted with the JNDI API, which will be the foundation for all subsequent days' lessons. Today's session is devoted entirely to learning the concepts of naming and directory services and their use in enterprise Java applications. You will end the day by writing a simple restaurant application that uses the JNDI API.