What is the purpose of private in Java?

In Java, the private keyword is used to modify the class member variables and methods, restricting them to only be accessible within the current class and not directly accessible by other classes.

Specifically, the role of private includes the following aspects:

1. Encapsulation: The use of the private keyword allows the hiding of internal details of a class, making them only visible within the class itself. This prevents external classes from directly modifying the internal state of the class, thus enhancing the encapsulation and security of the code.
2. Data encapsulation: By declaring member variables as private, access to the data of a class can be controlled. External classes cannot directly access or modify private member variables, they can only indirectly manipulate them through the class’s public methods (getters and setters).
3. Prevent accidental modifications: the private keyword can prevent other classes from accidentally modifying the internal state or data of a class. Only methods within the class can directly manipulate private member variables, and external classes cannot bypass the class’s public methods to make changes.

In short, the purpose of the ‘private’ keyword is to protect the internal state and data of a class, increase encapsulation, and improve the safety and maintainability of the code.