It allows a class (called a subclass or child class) to inherit fields and methods from another class (called a superclass or parent class).
🔹 Why Use Inheritance?

  • Reusability: Reuse code from existing classes.
  • Extensibility: Extend or add new features to existing classes.
  • Maintainability: Easier to manage code.
  • Polymorphism: Allows a subclass to be treated as an instance of its superclass. 🔸 Basic Syntax 
class Parent {
    void display() {
        System.out.println("This is the parent class");
    }
}

class Child extends Parent {
    void show() {
        System.out.println("This is the child class");
    }
}

public class Main {
    public static void main(String[] args) {
        Child obj = new Child();
        obj.display();  // Inherited method
        obj.show();     // Child's own method
    }

}

🔹 Types of Inheritance in Java

Single Inheritance

-One class inherits from another.

Multilevel Inheritance

A class inherits from a derived class.

Hierarchical Inheritance

Multiple classes inherit from a single parent class.

❌ Multiple Inheritance (via classes) is not supported in Java (to avoid ambiguity issues like the Diamond Problem).

✅ But Java supports multiple inheritance using interfaces.

🔸 super Keyword
Used to:

Access superclass methods or constructors.

class Parent {
    void greet() {
        System.out.println("Hello from parent");
    }
}

class Child extends Parent {
    void greet() {
        super.greet(); // Call parent version
        System.out.println("Hello from child");
    }
}

🔸 Access Modifiers in Inheritance

  • private: Not accessible in child class.
  • protected: Accessible in child class, even if it's in a different package.
  • public: Always accessible.
  • default (no modifier): Accessible in the same package only.

🔹 Why We Use super() in Java:

  1. To call the parent class constructor:
  • When a subclass is created, it often needs to initialize things from its parent class. super() lets you do that.
  • It must be the first statement in the subclass constructor.
  1. To reuse parent class initialization code, instead of rewriting it in the child class.

🔸 When you don't write super() explicitly:

Java automatically inserts a default super() call if there’s no constructor with parameters in the parent class.
🔹 Other Forms of super (not super()) **(tbd)**

Besides super() (constructor call), Java also allows:

  • super.someMethod() → Call a method from the parent class.
  • super.someVariable → Access a variable from the parent class.