Inheritance is not the only way of constructing adaptable objects. You can achieve similar goals by using a concept named composition.

This concept models another kind of relation between objects; it models what is called a has a relation.

Examples:

• a Laptop has a network card;
• a Hovercraft has a specific engine.

Composition is the process of composing an object using other different objects. The objects used in the composition deliver a set of desired traits (properties and/or methods) so we can say that they act like blocks used to build a more complicated structure.

It can be said that:

• inheritance extends a class's capabilities by adding new components and modifying existing ones; in other words, the complete recipe is contained inside the class itself and all its ancestors; the object takes all the class's belongings and makes use of them;
• composition projects a class as a container (called a composite) able to store and use other objects (derived from other classes) where each of the objects implements a part of a desired class's behavior. It’s worth mentioning that blocks are loosely coupled with the composite, and those blocks could be exchanged any time, even during program runtime.