What are Access Modifiers?

Access modifiers are keywords in Java that define the accessibility of classes, methods, constructors and variables.

They help us control where a particular member can be accessed.

Types of Access Modifiers

Java provides four access modifiers:

  1. public
  2. private
  3. protected
  4. default

1) Public

The public modifier allows a member to be accessed from anywhere, including other packages.

public class Student { public String name = "John"; public void display() { System.out.println(name); } }

Here, the name variable and display() method can be accessed from anywhere.

2) Private

The private modifier allows a member to be accessed only within the same class.

public class Student { private int age = 22; private void display() { System.out.println(age); } }

Here, the age variable and display() method cannot be accessed directly outside the Student class.

3) Protected

The protected modifier allows a member to be accessed:

  • Within the same class.
  • Within the same package.
  • In subclasses belonging to other packages, subject to Java's inheritance access rules. 
class Student { protected String name = "John"; } class Details extends Student { void display() { System.out.println(name); } }

Here, the Details class can access the protected name variable through inheritance.

4) Default

When we don't specify any access modifier, Java uses the default access level, also called package-private.

It allows members to be accessed only within the same package.

class Student { String name = "John"; void display() { System.out.println(name); } }

Here, both name and display() can be accessed by classes within the same package.

Access Modifier Comparison

Modifier Same Class Same Package Subclass (Different Package) Other Packages
public Yes Yes Yes Yes
protected Yes Yes Yes* No
default Yes Yes No No
private Yes No No No

*Protected access in another package is available through inheritance, with additional access restrictions.

Important Points

  • Java has four access levels: public, private, protected and default.
  • Private members can only be accessed within their own class.
  • Default access is limited to the same package.
  • Protected access supports inheritance across packages.
  • Public members can be accessed from anywhere.
  • Top-level classes can only use public or default access modifiers.

That's it! Access modifiers help us control the visibility of members and are an important part of encapsulation in Java.