JNDI provides a common-denominator interface to many existing naming services. Let's begin by taking a look at some of these services. The figure below depicts the organization of a generic naming service. A generic naming service A naming service maintains a set of bindings. Bindings relate names to objects.
Clients use the naming service to locate objects by name.
There are a number of existing naming services, a few of which I'll describe below. They each follow the pattern above, but differ in the details. Interestingly, DNS is a distributed naming service, meaning that the service and its underlying database is spread across many hosts on the Internet. Network naming services developed by Sun Microsystems. Both allow users to access files and applications on any host with a single ID and password.