Access Protection

Java provides four main access modifiers that define the visibility and accessibility of classes, methods, variables, and constructors. These are public, protected, default (no keyword), and private. Let’s discuss them in detail:

1. public Access Modifier:

• Scope: Accessible from anywhere in the program (same class, same package, subclasses, and other packages).
• Usage: Used for classes, methods, and variables to make them universally accessible.

Syntax:

public class MyClass {
    public void display() {
        System.out.println("Public Method");
    }
}Code language: PHP (php)

2. protected Access Modifier:

• Scope: Accessible within the same package and by subclasses in different packages (through inheritance).
• Usage: Used to provide access to subclasses while restricting access to non-subclasses in different packages.

Syntax:

class Parent {
    protected void show() {
        System.out.println("Protected Method");
    }
}Code language: JavaScript (javascript)

3. default (Package-Private) Access Modifier:

• Scope: Accessible only within the same package. It is the default modifier when no explicit access modifier is specified.
• Usage: Used for restricting access to package-level visibility.

Syntax:

class PackageClass {
    void display() {
        System.out.println("Default Access");
    }
}Code language: JavaScript (javascript)

4. private Access Modifier:

• Scope: Accessible only within the same class. Not visible to other classes, even in the same package.
• Usage: Used to achieve encapsulation and prevent external modification of critical data.

Syntax:

class BankAccount {
    private double balance;

    private void calculateInterest() {
        System.out.println("Private Method");
    }
}Code language: PHP (php)