Difference between Inheritance and Composition

Question

Are Composition and Inheritance the same? If I want to implement the composition pattern, how can I do that in Java?

Answer 1

Composition means HAS A
Inheritance means IS A

Example: Car has a Engine and Car is a Automobile

In programming this is represented as:

class Engine {} // The Engine class.

class Automobile {} // Automobile class which is parent to Car class.

class Car extends Automobile { // Car is an Automobile, so Car class extends Automobile class.
  private Engine engine; // Car has an Engine so, Car class has an instance of Engine class as its member.
}