Java Inheritance

Java Inheritance (Subclass and Superclass)

In Java, it is possible to inherit attributes and methods from one class to another. We group the "inheritance concept" into two categories:

• Subclass (child) - the class that inherits from another class
• Superclass (parent) - the class being inherited from

To inherit from a class, use the extends keyword.

Example

class Vehicle {
  protected String brand = "Ford"; // Vehicle attribute
  public void honk() { // Vehicle method
    System.out.println("Tuut, tuut!");
  }
}
 
class Car extends Vehicle {
  private String modelName = "Mustang"; // Car attribute
  public static void main(String[] args) {
    Car myCar = new Car();
    myCar.honk();
    System.out.println(myCar.brand + " " + myCar.modelName);
  }
}

Did you notice the protected modifier in Vehicle? If it was set to private, the Car class would not be able to access it.

Why And When To Use "Inheritance"?

• It is useful for code reusability: reuse attributes and methods of an existing class when you create a new class.

The final Keyword

If you don't want other classes to inherit from a class, use the final keyword:

final class Vehicle {
  ...
}
 
class Car extends Vehicle {
  ...
}