Which is a key aspect of composition?

Which is a key aspect of composition?

A.
Using inheritance

B.
Method delegation

C.
Creating abstract classes

D.
Implementing the composite interface

Explanation:

In the composition approach, the subclass becomes the “front-end class,” and the superclass
becomes the”back-end class.” With inheritance, a subclass automatically inherits an
implemenation of any non-privatesuperclass method that it doesn’t override. With composition, by
contrast, the front-end class must explicitlyinvoke a corresponding method in the back-end class
from its own implementation of the method. This explicitcall is sometimes called “forwarding” or
“delegating” the method invocation to the back-end object.Note: Composition means the same as:
* contains
* is part of
Note 2: As you progress in an object-oriented design, you will likely encounter objects in the
problem domainthat contain other objects. In this situation you will be drawn to modeling a similar
arrangement in the design ofyour solution. In an object-oriented design of a Java program, the
way in which you model objects that containother objects is with composition, the act of
composing a class out of references to other objects. Withcomposition, references to the
constituent objects become fields of the containing object. To use compositionin Java, you use
instance variables of one object to hold references to other objects.