JNDI

JNDI - Java Naming and Directory Interface

• The JNDI is a Java API for a directory service that allows Java software clients to discover and lookup data and objects via a name.
• Like all Java APIs, that interface with host systems, JNDI is independent of the underlying implementation.

Click here to see: JNDI Architecture

• Aditionally, It specifies a Service Provider Interface (SPI) that allows directory service implementations (like LDAP, DNS, NIS and etc...) to be plugged in to framework. It may make use of a server, a flat file, or a database; the choice upto the vendor.
• JNDI is defined to be independent of any specific directory service implementation. Thus a variety of directories new, emerging and already deployed can be accessed in a common way.

• The JNDI API is used by RMI and JEE APIs to lookup objects in a network.
• JNDI API provides
• A mechanism to bind an object to a name.
• A directory lookup interface that allows general queries.

• To provide Global visibility to Java objects and their references we keep them in registry software.
• Every Web server/ Application server gives a registry software
• Weblogic --> Weblogic registry
• Tomcat --> Tomcat registry
• Glassfish --> Glassfish registry
• JBoss --> JNP registry

• Java Applications use JDBC API (java.sql, javax.sql packages) to interact with Database software.
• Java Applications use JNDI API (javax.naming and its subpackages) to interact with Registry software.
• JDBC, JNDI are part of JSE module(JDK s/w).

• Multiple Java Applications can use an object which was stored in JNDI Registry as shown in above diagram.

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References:

1. Oracle docs: http://docs.oracle.com/javase/jndi/tutorial/getStarted/overview/index.html

2. Wikipedia: http://en.wikipedia.org/wiki/Java_Naming_and_Directory_Interface
3. Natraj: http://www.nataraz.in/