What is JNDI?

What is JNDI?

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Java Naming and Directory Interface (JNDI) is a Java API for a directory service that allows Java software clients to discover and look up data and objects via a name. Like all Java APIs that interface with host systems, JNDI is independent of the underlying implementation. Additionally, it specifies a service provider interface (SPI) that allows directory service implementations to be plugged into the framework. The implementations may make use of a server, a flat file, or a database; the choice is up to the vendor.

JNDI organizes its names into a hierarchy. A name can be any string such as "com.mydomain.ejb.MyBean". A name can also be an object that supports the Name interface; however, a string is the most common way to name an object. A name is bound to an object in the directory by storing either the object or a reference to the object in the directory service identified by the name.

The JNDI API defines a context that specifies where to look for an object. The initial context is typically used as a starting point. JNDI works in concert with other technologies in the Java Platform, Enterprise Edition (Java EE) to organize and locate components in a distributed computing environment.

In the simplest case, an initial context must be created using the specific implementation and extra parameters required by the implementation. The initial context will be used to look up a name. The initial context is analogous to the root or top of a directory tree for a file system.

The JNDI API is used by the Java RMI and Java EE APIs to look up objects in a network. JINI has its own lookup service and does not use the JNDI API.

The API provides the following features:

1. A mechanism to bind an object to a name


2. A directory lookup interface that allows general queries


3. An event interface that allows clients to determine when directory entries have been modified


4. LDAP extensions to support the additional capabilities of an LDAP service

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