LDAP Package

This package contains classes and interfaces for using LDAP v3-specific features that are not already covered by the more generic javax.naming.directory package. In fact, the majority of JNDI applications that use the LDAP will find the javax.naming.directory package sufficient, and will not need to use this package at all. This package is primarily for those applications that need to use extended operations, controls, or unsolicited notifications.

Extended Operation
In addition to specifying well-defined operations such as search and modify, the LDAP v3 protocol (RFC 2251) specifies a way of transmitting yet-to-be defined operations between the LDAP client and server. These operations are referred to as extended operations. An extended operation may be defined by a standards organization such as the IETF or by a vendor.
Controls
The LDAP v3 protocol (RFC 2251) allows any request or response to be augmented by yet-to-be defined modifiers. These modifiers are referred to as controls . Controls that are sent with requests are called request controls and those that are sent with responses are called response controls . A control may be defined by a standards organization such as the IETF or by a vendor. There is not necessarily a pairing between request controls and response controls.
Unsolicited Notifications
In addition to the normal request/response style of interaction between the client and server, the LDAP v3 protocol (RFC 2251) also specifies unsolicited notifications--messages that are sent from the server to the client asynchronously, not in response to any client request.
The LDAP Context
The LdapContext interface represents a context for performing extended operations, sending request controls, and receiving response controls.
Examples of how to use these features are described in the Controls and Extensions lesson.

JNDI Overview