Java Access Modifiers

The Java access modifiers are keywords that control the visibility and accessibility of classes, fields, methods, and other members within your code. They play a crucial role in maintaining encapsulation, controlling who can access or modify elements in your code, and ensuring data privacy and security. Java provides four main access modifiers:

1. public:

• Members (classes, fields, methods, etc.) marked as public are accessible from any class or package.
• There are no access restrictions, and public members are part of the API for the class.
• For example, a public method in a class can be called from any other class.

   public class MyClass {
       public int myPublicField;
       public void myPublicMethod() {
           // Code here
       }
   }

2. protected:

• Members marked as protected are accessible within the same package and by subclasses, even if they are in different packages.
• This modifier is often used to implement inheritance and provide a degree of encapsulation.
• For example, a protected field is accessible in subclasses but not by classes in unrelated packages.

   class MyBaseClass {
       protected int myProtectedField;
   }

   public class MySubClass extends MyBaseClass {
       void accessProtectedField() {
           int x = myProtectedField; // Access to the protected field
       }
   }

3. default (Package-Private):

• When no access modifier is specified (i.e., no public, protected, or private), the default access modifier is used.
• Members marked as default are accessible only within the same package. They are not accessible from outside the package.

   class MyClass {
       int myDefaultField; // Package-private access
   }

4. private:

• Members marked as private are the most restrictive. They are only accessible within the same class.
• This provides the highest level of encapsulation and data hiding.
• Typically used to hide the internal implementation details of a class.

   public class MyClass {
       private int myPrivateField;
       private void myPrivateMethod() {
           // Code here
       }
   }

Here’s a summary of the access modifiers and their visibility:

public	Accessible from anywhere, including other packages.
protected	Accessible within the same package and by subclasses.
default	Accessible only within the same package.
private	Accessible only within the same class.

It’s important to use access modifiers appropriately to ensure that your code is secure, maintainable, and follows the principles of encapsulation. Good use of access modifiers helps create clear, well-structured code and promotes code reusability.