Java OPP stands for Object-Oriented Programming in Java. It is a programming paradigm that focuses on creating objects that contain both data and methods to manipulate that data. In Java, objects are instances of classes, which are templates or blueprints for creating objects.

Java OPP allows for the organization of code into reusable and modular components, making it easier to understand, maintain, and extend. It promotes concepts such as encapsulation, inheritance, and polymorphism.

Encapsulation refers to the bundling of data and methods within a class, hiding the internal implementation details and providing a public interface for interacting with the object. This helps in achieving data abstraction and data security.

Inheritance allows for the creation of new classes based on existing classes, inheriting their properties and behaviors. It promotes code reuse and allows for the creation of class hierarchies.

Polymorphism allows objects of different classes to be treated as objects of a common superclass. It enables the use of a single interface to represent different types of objects, providing flexibility and extensibility.

Overall, Java OPP provides a structured and modular approach to programming, making it easier to develop complex applications and maintain codebases.