Access modifiers

Public

Keyword: public
Access: Accessible from anywhere (inside/outside the class, package, or project).
Usage: Typically used for classes, methods, and variables that need global access.

Example

public class MyClass {
    public int value = 10;
    public void display() {
        System.out.println("Public method");
    }
}

Private

Keyword: private
Access: Accessible only within the same class.
Usage: Used to hide class fields or methods, following the principle of encapsulation.

Example

public class MyClass {
    private int value = 10; // Not accessible outside this class

    private void display() {
        System.out.println("Private method");
    }
}

Protected

Keyword: protected
Access: Accessible within the same package and by subclasses (even if outside the package).
Usage: Useful when extending classes across packages.

Example

public class MyClass {
    protected int value = 10;

    protected void display() {
        System.out.println("Protected method");
    }
}

Note

If accessed by a subclass in a different package, it must be through inheritance (not directly via an instance).

Package-Private

Keyword: No keyword (Default Access)
Access: Accessible only within the same package.
Usage: Used for classes and members that don’t need to be accessed outside their package.

Example

class MyClass { // No access modifier, so it's package-private
    int value = 10;

    void display() {
        System.out.println("Package-private method");
    }
}

Note

Package-private is the default if no modifier is specified.

Access Summary

Modifier	Same Class	Same Package	Subclass (Different Package)	Other Packages
public	✅	✅	✅	✅
protected	✅	✅	✅ (via inheritance)	❌
(default)	✅	✅	❌	❌
private	✅	❌	❌	❌

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