JNDI

Java Naming Directory Interface

JNDI is an API specified in Java that provides naming and directory functionality to applications written in Java. JNDI was developed by Sun as a regular or standard extension to Java programming Language JNDI is designed especially for Java by using Java’s object model.

JNDI is used by Java applications can store and retrieve named Java objects of any type. JNDI provides methods for performing standard directory operations. Examples: Associating attributes with objects and searching for objects using their attributes.

JNDI is defined independent of any specific naming or directory service implementation. JNDI enables Java applications to access different, naming and directory services using a common API. Different naming and directory service proider can be plugged in seamlessly behind the common API.

The common API allows Java applications to take advantage of information in a variety of existing naming and directory services, and allows Java applications to coexist with legacy applications and systems. Examples: such as LDAP, NDS, DNS, and NIS(YP).

JNDI Architecture

JNDI has three layers and exposes two interfaces: an API for Java clients and servers to use and a Service Providers Interface (SPI) for vendors who provide JNDI services. The Naming Manager layer maps each JNDI call to a service provider.

The standardization of these two interfaces makes the service provider almost transparent to the Java application code. Clients can use the JNDI API to bind and lookup over a wide range of naming services.

How Does JNDI Services Work Each JNDI service vendor is free to implement the set of naming and directory services. They choose to support in their own way.

All of the names in a naming system comprise the system’s namespace. The naming systems use their own naming conventions. A naming convention defines atomic names, which can’t be divided, and compound names, conglomerates of atomic names that organize similar names in the same namespace.

Using JNDI as a tool, the Java application developer can build new powerful and portable applications that not only take advantage of Java’s object model but are also well integrated with the environment in which they are deployed. Example of where JNDI is used: –JMS -Java Messaging Service –JDBC -Java Database Connectivity package –EJB - Enterprise Java Beans