Encapsulation is a fundamental concept in object-oriented programming (OOP) that refers to the bundling of data and methods that operate on that data within a single unit, which is called a class in Java and other OOP languages). Encapsulation allows developers to present a consistent and usable interface that is independent of how a system is implemented internally). It also allows developers to hide the values or state of a structured data object inside a class, preventing direct access to them by clients in a way that could expose hidden implementation details or violate state invariance maintained by the methods).

Encapsulation can be used to restrict direct access to some components of an object, so users cannot access state values for all of the variables of a particular object. By hiding the internals of the object, encapsulation protects its integrity). Encapsulation provides the basic property to hide data, thereby providing security to user data.

In summary, encapsulation is a way to bundle data and methods that work on that data within one unit, like a class in Java, and restrict direct access to some components of an object to protect its integrity and provide security to user data).