Access Modifiers in Java

A.

Using the private modifier is the main way that an object encapsulates itself and hide data from the outside world.

The correct answer to this question is A. Encapsulation.

Encapsulation is a fundamental concept in object-oriented programming (OOP) that involves grouping related variables and methods together into a single unit, which is referred to as a class. In Java, classes are used to define objects, which are instances of the class.

Access modifiers are keywords in Java that are used to restrict the visibility or accessibility of variables, methods, and classes. There are four access modifiers in Java:

• public: The variable, method, or class can be accessed from anywhere, both within and outside the package.
• private: The variable, method, or class can only be accessed from within the class in which it is declared.
• protected: The variable, method, or class can be accessed within the same package or from a subclass in a different package.
• default: The variable, method, or class can only be accessed within the same package.

In encapsulation, access modifiers are used to protect the variables within a class and to hide them from other classes. This is done by declaring the variables as private, which means they can only be accessed from within the same class. The class provides public methods, also known as getters and setters, to access and modify the values of the private variables.

By using encapsulation, the implementation details of a class can be hidden from other classes, which promotes data integrity and security. It also makes it easier to change the implementation of a class without affecting other classes that use it, as long as the public methods remain the same.

In summary, encapsulation is the Java concept that uses access modifiers to protect variables and hide them within a class.