The Java OOP principles are: 1. Encapsulation: Bundles data and methods within a class, restricting direct access to some of its components to protect the data. 2. Inheritance: Allows a class to inherit properties and behaviors from another class, promoting code reuse. 3. Polymorphism: Enables one interface or method to be used for different data types or objects, allowing flexibility in code. 4. Abstraction: Hides complex implementation details and shows only the necessary functionalities to the user through abstract classes or interfaces.