Programming

2. Without using the inheritance, Is it
possible to inherit the property of
another class?
How??
Using
Association

3. Relationship Between Classes
Inheritance
• Is-A
• extends
• Blood relation
• Tightly coupled
Association
• Is-A
• Reference variable, new
• No Blood relation
• Not Tightly coupled

4. • Association establishes a relationship between any two objects.
• Objects have an independent lifecycle i.e.) no ownership between the
objects.
Association

5. Association
Prime
Minister
Minister-1
Minister-2
Minister-n
Defense
Finance
External
Affairs
Internal
Affairs
More…
People
Country

6. Association
Aggregation
Composition
Association

7. Association
CAR
Music_Player Engine
Aggregation Composition

8. Association
University
Anna University VIT University
Is-A Is-A
Professor
[Weak]
Branches
(Mech, EEE, CSE)
[Strong]
Has-A Has-A

9. // Predict the output
import java.util.*;
class Company
{
private String name;
Company(String name) {
this.name = name;
}
public String getCompanyName() {
return this.name;
}
}
class Employee
{
private String name;
Employee(String name){
this.name = name;
}
public String getEmployeeName() {
return this.name;
}
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10. public class Association
{
public static void main (String[] args)
{
Scanner sc = new Scanner(System.in);
String c_name = sc.next();
String e_name = sc.next();
Company c = new Company(c_name);
Employee emp = new Employee(e_name);
System.out.println(emp.getEmployeeName() + " is employee of " +
c.getCompanyName());
}
}
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11. Composition
 It represents part – of relationship
 Both classes are highly dependent on each other
 Example:
Every human has a heart (part - of relationship)
Human and heart(Dependent on each other)
Books and Authors(Dependent on each other)

12. // Predict the output
class Book{
String author;
String title;
Book(String author, String title){
this.author = author;
this.title = title;
}
}
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13. public class Library {
Book book;
Library(Book book){
this.book = book;
}
public static void main(String[] args) {
Book b = new Book("Shakespeare", "Julius caesar" );
Library library = new Library(b);
System.out.println(library.book.author);
System.out.println(library.book.title);
}
}
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14. // Predict the output
class Address
{
private int doorNo;
private String rem;
public int getDoorNo(){
return doorNo;
}
public void setDoorNo(int doorNo){
this.doorNo = doorNo;
}
public String getRem(){
return rem;
}
public void setRem(String rem){
this.rem = rem;
}
public String toString(){
return " Address: " + doorNo + " ," + rem;
}
}
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15. class Person
{
private String Name;
private Address address;
public Person()
{
address = new Address();
}
public void setName(String Name)
{
this.Name = Name;
}
public Address getAddress()
{
return address;
}
public String toString()
{
return "Person Name: " + Name + address ;
}
}
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16. public class Main {
public static void main(String args[]) {
Person person = new Person();
person.setName("Mahendra Singh Dhoni");
person.getAddress().setDoorNo(07);
person.getAddress().setRem("XXX, Ranchi, Jharkhand.");
System.out.println(person);
}
}
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public class Main {
public static void main(String args[]) {
Person person = new Person();
person.setName("Mahendra Singh Dhoni");
person.getAddress().setDoorNo(07);
person.getAddress().setRem("XXX, Ranchi, Jharkhand.");
System.out.println(person);
person = null;
if(person != null)
{
System.out.println(person.getAddress());
}
else
System.out.println("Address Does not Exist");
}
}

17. // Predict the output
class Engine {
public String toString() {
return "L-twin cylinder Engine";
}
}
class Bike {
String name;
private Engine engine;
public Bike(String name, Engine engine){
this.name=name;
this.engine = engine;
}
public Engine getEngine() {
return engine;
}
public void setEngine(Engine engine) {
this.engine = engine;
}
public String toString() {
return name + " Bike " + "uses " + engine; }
}
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18. public class Main {
public static void main(String[] args) {
Engine engine = new Engine();
Bike bike = new Bike(“Ducati",engine);
System.out.println(engine);
System.out.println(bike);
}
}
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public class Main {
public static void main(String[] args) {
Engine engine = new Engine();
Bike bike = new Bike(“Ducati",engine);
bike = null;
System.out.println(engine);
System.out.println(bike);
}
}

19. THANK YOU