When you're working with object-oriented programming, it's important to understand access modifiers. These are rules that help manage who can see and use different parts of a class, like its properties and methods. The main access modifiers are public, protected, and private. Each has its own rules for how subclasses, or classes that inherit from another class, can access them. Let's break down what these modifiers mean and how they affect inheritance.

Access Modifiers Explained

1. Public:

   • Public members can be accessed from anywhere in the program.
   • This means that both subclasses and other classes can use them.
   • Having public members makes it easy for developers to interact with these parts of the class.

   Example:

   class Animal {
       public void eat() {
           System.out.println("Animal is eating");
       }
   }
   
   class Dog extends Animal {
       public void bark() {
           System.out.println("Dog is barking");
       }
   }
   

   Here, a Dog can call the eat method from Animal because it's public.

2. Protected:

   • Protected members can only be accessed within the same class or by subclasses.
   • This means only the class that defines them and its children can use them.
   • This keeps some privacy but allows subclasses access to certain features.

   Example:

   class Animal {
       protected int age;
   
       protected void grow() {
           age++;
       }
   }
   
   class Dog extends Animal {
       public void celebrateBirthday() {
           grow();  // Can access the protected method
           System.out.println("Dog's age now is " + age);
       }
   }
   

   In this case, Dog can access and change age because it's protected.

3. Private:

   • Private members can only be used within the class they belong to.
   • They cannot be accessed by subclasses or any other class.
   • This helps keep important information safe and hidden.

   Example:

   class Animal {
       private String name;
   
       private void setName(String name) {
           this.name = name;
       }
   }
   
   class Dog extends Animal {
       public void setDogName(String name) {
           // setName(name);  // This will cause an error because it’s private
       }
   }
   

   In this case, Dog cannot access setName or name because they are private.

Summary of Differences

• Public:

  • Can be accessed from anywhere.
  • All parts of other classes and subclasses can use it.
  • Easy to use but might expose too much information.

• Protected:

  • Can be used inside its own class and by subclasses.
  • Allows inheritance while keeping some parts hidden.
  • Balances accessibility and privacy.

• Private:

  • Can only be accessed within the class it is defined in.
  • Not inherited by subclasses.
  • Promotes privacy and protects important data inside the class.

Conclusion

Choosing the right access modifier is very important for how classes and subclasses work together. Knowing the differences between public, protected, and private helps developers create strong and easy-to-understand code. Understanding these modifiers leads to better programming practices and helps prevent errors in code. Access modifiers are key to making sure our software is organized and works well together.