[Java] Aggregation in java

Aggregation in java

- If a class have an entity reference, It is known as Aggregation

1. Why use Aggregation

- For code Reuseability

2. Example

1) Address.java

public class Address { String city, state, country; public Address(String city, String state, String country){ this.city = city; this.state = state; this.country = country; } }

2) Emp.java

public class Emp { int id; String name; Address address; public Emp(int id,String name, Address address){ this.id = id; this.name = name; this.address = address; } void display(){ System.out.println(id + name); System.out.println(address.city + address.country); } public static void main(String[]args){ Address ad1 = new Address("seoul","Up","kor"); Emp e1 = new Emp(111,"KYLE",ad1); e1.display(); } }