Relationship in java

type of relationship always makes to understand how to reuse the feature from one class to another class. in java programming we have three types of relationship they are:-

. IS-A relationship (Inheritance)

. HAS-A relationship (Aggregation)

. User -A relationship

IS-A relationship

In an IS-A relationship, one class is obtaining the feature of another

class by using inheritance concept with extend keyword.

NOTE:- in an IS-A relationship there exists

logical memory space

Note:- the default relationship in java is IS-A because for

each and every class in java there exists an implicit

predefined superclass in java. lang.object

HAS-A relationship

In HAS-A relationship an object of one class is created as a

data member in another class the relationship between these

two classes in HAS-A

In HAS-A relationship there existed physical memory space

and it is also known as part of or kind of relationship

User -A relationship

A method of one class is using an object of another class the

relationship between these two classes is known as user-A relationship.

What is Inheritance ?

The process of obtaining the data members and methods from

one class to another class is known as inheritance

Type of Inheritance

. single

. multi-level

. multiple

single

In single inheritance one parent and one child class

multi-level

In multi-level inheritance derived from derived class

multiple

In multiple inheritances multiple parent but single child

Relationship in java