What are the method access control levels supported by the Java function overloading mechanism?

Java function overloading allows the creation of functions with different signatures but the same name. Visibility is controlled by the access control level, which supports private, package-level private, protected and public. For example, the calculateArea() function can be overloaded to accept a circle or square argument and be accessed from different locations depending on the access control level.

Access control level of Java function overloading

Function overloading in Java allows the definition of multiple functions with the same name but different signatures function. These functions can have different parameter types, number of parameters, and return types. In function overloading, the access control level determines the visibility of different versions of the overloaded method to different packages and classes.

Access control levels supported by Java function overloading

The Java language supports the following access control levels:

• private ): Can only be accessed from within the class in which they are defined.
• Package-private (package-private): Can only be accessed from classes within the package that contains them.
• Protected: Can only be accessed from classes and derived classes in the package that contains them.
• Public (public): Can be accessed from any class.

Practical Case

Consider the following example where the overloaded calculateArea() function accepts values ​​based on shape (circle or square) Different parameters:

public class ShapeCalculator {

    public double calculateArea(Circle circle) {
        return Math.PI * circle.getRadius() * circle.getRadius();
    }

    public double calculateArea(Square square) {
        return square.getWidth() * square.getWidth();
    }
}

In this example, we declare two versions of the calculateArea() function:

• calculateArea(Circle circle ) Receives a circular object as a parameter and returns the area of ​​the circle.
• calculateArea(Square square) Receives a square object as a parameter and returns the area of ​​the square.

Both versions of the calculateArea() function can be accessed from any class because they are both declared as public. Therefore, we can use these functions in any of the following locations:

• Classes within the same package
• Classes within different packages
• From the main method

It should be noted that the access control level is also important for overriding and rewriting different versions of overloaded methods. For example, in a subclass, you can only override parent class methods that have the same or broader access control level.

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