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The book is a key dive into Object Oriented Programming using Java., Study notes of Object Oriented Programming

Kenyatta UniversityObject Oriented Programming

The book focuses on Java, Object, classes and all the basic a student need to cover as far as revision is concerned.

Typology: Study notes

2012/2013

Uploaded on 11/30/2023

ian-2oe
ian-2oe 🇰🇪

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The answer of OOP Final Exam 2nd – MCs RADHWAN
2017
1
Q1 answer any two of following:
a. What is this in java?
There can be a lot of usage of java this keyword. In java, this is a reference variable that
refers to the current object.
b. What is polymorphism in java?
Polymorphism in java is a concept by which we can perform a single action by different
ways
c. Why use Java encapsulation?
Encapsulation in java is a process of wrapping code and data together into a single unit,
For example capsule i.e. mixed of several medicines.
Q2 what is an inheritance and which types are supported in java? Explain that with a source
code example.
Solution:-
Inheritance in java is a mechanism in which one object acquires all the properties and behaviors
of parent object.
The idea behind inheritance in java is that you can create new classes that are built upon existing
classes. When you inherit from an existing class, you can reuse methods and fields of parent
class, and you can add new methods and fields also.
There can be three types of inheritance in java: single, multilevel and hierarchical.
pf3
pf4
pf5

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Download The book is a key dive into Object Oriented Programming using Java. and more Study notes Object Oriented Programming in PDF only on Docsity!

Q1 answer any two of following:

a. What is this in java?

There can be a lot of usage of java this keyword. In java, this is a reference variable that

refers to the current object.

b. What is polymorphism in java?

Polymorphism in java is a concept by which we can perform a single action by different

ways

c. Why use Java encapsulation?

Encapsulation in java is a process of wrapping code and data together into a single unit,

For example capsule i.e. mixed of several medicines.

Q2 what is an inheritance and which types are supported in java? Explain that with a source

code example.

Solution:-

Inheritance in java is a mechanism in which one object acquires all the properties and behaviors

of parent object.

The idea behind inheritance in java is that you can create new classes that are built upon existing

classes. When you inherit from an existing class, you can reuse methods and fields of parent

class, and you can add new methods and fields also.

There can be three types of inheritance in java: single, multilevel and hierarchical.

Single Inheritance Example

  1. class Animal{
  2. void eat(){System.out.println("eating...");}
  3. }
  4. class Dog extends Animal{
  5. void bark(){System.out.println("barking...");}
  6. }
  7. class TestInheritance{
  8. public static void main(String args[]){
  9. Dog d= new Dog();
  10. d.bark();
  11. d.eat();
  12. }}

Multilevel Inheritance Example

  1. class Animal{
  2. void eat(){System.out.println("eating...");}
  3. }
  4. class Dog extends Animal{
  5. void bark(){System.out.println("barking...");}
  6. }
  7. class BabyDog extends Dog{
  8. void weep(){System.out.println("weeping...");}
  9. }
  10. class TestInheritance2{
  11. public static void main(String args[]){
  12. BabyDog d= new BabyDog();
  13. d.weep();
  14. d.bark();
  15. d.eat();
  16. }}

Hierarchical Inheritance Example

  1. class Animal{
  2. void eat(){System.out.println("eating...");}
  3. }
  4. class Dog extends Animal{

Q4 Using abstraction concept on superclass: write a program for employee class contains the

variable (ID, name, mobile-no and salary) do the following operations:

1. Initial values for 4 Employee.

2. Display the information of Employee who has name = Ahmad.

Solution:-

package uot;

abstract public class Studentt {

int ID;

String name;

long MobileNo;

float Salary;

abstract void insert(int ID, String name, long MobileNo, float Salary);

abstract void display();

class student extends Studentt{

int ID;

String name;

long MobileNo;

float Salary;

void insert(int ID, String name, long MobileNo, float Salary){

this.ID=ID;

this.name=name;

this.MobileNo=MobileNo;

this.Salary=Salary;

void display(){

if (name=="Ahmad") {

System.out.println(ID+" "+name+" "+MobileNo+" "+Salary);

public static void main(String[] args) {

student s=new student();

student s1=new student();

student s2=new student();

student s3=new student();

s.insert(10,"Ali",07701111110,80.000f);

s1.insert(11,"Ahmad",0770111111,50.000f);

s2.insert(13,"sara",07701111112,90.000f);

s3.insert(16,"lee",07701111113,100.000f);

System.out.println("==========the Employee who has name = Ahmed is ========");

s.display();

s1.display();

s2.display();

s3.display();

Q5 Using polymorphism and inheritance: write a program to display the names of shapes

(rectangle, square and circle)?

Solution:-

package uot;

class Shape{

void area(){

System.out.println("shape");

class rectangle extends Shape{

void area(){

System.out.println("rectangle");

class square extends Shape{

void area(){

System.out.println("square");

class circule extends Shape{

void area(){

System.out.println("circule");

if (mark<5){

mark=mark+2;

System.out.println("have carve 2 marks for student "+" "+rollno+" "+name+" "+subject+"

"+mark);

else {

System.out.println("no mark for student "+" "+rollno+" "+name+" "+subject+" "+mark);

public static void main(String[] args) {

student s=new student(10,"ali","oop",6);

student s1=new student(12,"rad","oop",3);

student s2=new student(13,"sara","oop",2);

student s3=new student(16,"lee","oop",7);

System.out.println("==========the student who have roll-no = 10 is =============");

s.display();

s1.display();

s2.display();

s3.display();

System.out.println("===========the marks <5 after carve===================");

s.carve();

s1.carve();

s2.carve();

s3.carve();