Benefits of using Composition: Composition allows us to reuse the code . In Java, we can use multiple Inheritance by using the composition concept. The Composition provides better test-ability of a class. Composition allows us to easily replace the composed class implementation with a better and improved version.
Read moreIS-A relationship in oops?
In OOP, IS-A relationship is completely inheritance . This means, that the child class is a type of parent class. For example, an apple is a fruit. So you will extend fruit to get apple.
Read more