Question 18 What is output? public abstract class People { protected String name; protected int age; public abstract void PrintInfo(); public void PrintInformation() { System.out.println("In Base Class People"); } } public class Teacher extends People { private int experience; public void PrintInfo() { System.out.println("In Child Class Teacher"); } } public class Principal extends Teacher { public void PrintInformation() { System.out.println("In Child Class Principal"); } public static void main(String args[]) { Principal tim; tim = new Principal(); tim.PrintInfo(); } } Error: Compiler error In Base Class People O In Child Class Teacher O In Child Class Principal

Question 18 What is output? public abstract class People { protected String name; protected int age; public abstract void PrintInfo(); public void PrintInformation() { System.out.println("In Base Class People"); } } public class Teacher extends People { private int experience; public void PrintInfo() { System.out.println("In Child Class Teacher"); } } public class Principal extends Teacher { public void PrintInformation() { System.out.println("In Child Class Principal"); } public static void main(String args[]) { Principal tim; tim = new Principal(); tim.PrintInfo(); } } Error: Compiler error In Base Class People O In Child Class Teacher O In Child Class Principal

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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public abstract class Shape { public Shape() { } public abstract double area() ; public String who() { return "Shape" ; } } public class Circle extends Shape { private int radius ; public Circle( int r ) { radius = r ; } @Override public double area() { return Math.PI * radius * radius ; } } public class Square extends Shape { private int _sideLength ; public Square( int sideLength ) { /* TODO question 45 */ } @Override public double area() { return _sideLength * _sideLength ; } } Implement the Square constructor, and make sure it throws an exception when the input parameter is not a valid length. The input parameter must be positive to be considered valid.
8. OOPS Theory #6 public class Car { public void horn() { System.out.println("Horn horn"); } } public class Ferrari extends Car { public void horn() { System.out.println("Ferarriiiiii"); } } public static void main(String[] args) { Ferrari ferrari = new Car(); ferrari.horn(); } Pick ONE option Horn horn Ferarriiii Cannot compile Runtime exception Clear Selection 9. OOPS Theory #7 In Java, we can achieve the abstraction by creating the blueprint of an object and only have abstract methods. What do we call this? Pick ONE option Interface Encapsulation Instance Protected Clear Selection
Find the Error. interface DAO{ public double getMax();public abstract double getAverage();} abstract class Human{ public abstract void study(); public void showValue(Number i){ System.out.println(i); }} class B extends Human implements DAO{ public void study() { System.out.println("Study OOP");}public double getMax() { return 30;}public double getAverage() { return 14.5;} @Overridepublic void getAccess() { System.out.println("233");}} public class AbstractionAndInterface {public static void main(String[] args) {Human h = new B();double res = h.getMax();System.out.println(res);B b = new B();System.out.println(b.getAverage());b.getAccess();}} public interface DAO2 {public void getAccess(); public abstract void printOutput();}
What is the output of the following code? Convert the abstract class into an interface and modify the codes in all classes that will maintain the same output. (Rewrite the code)
7. public class Father { public String name; public int age; // customer name Father(){ name="Hassan"; age=50;} public void display(){ System.out.println("Name:"+name); System.out.println("Age:"+age); }} Figure 3 i. Based on Figure 3, create a class named Child that inherits the Father class. Declare an instance name location (String) for class Child. ii. Define a constructor in class Child and give an appropriate initial values for the instance (name, age, location). Define a method display () in class Child, execute the display () method in superclass using the keyword super. Method display () in class Child should print the information of name, age and location. ii.
public class Father { public String name; public int age; // customer name Father(){ name=”Hassan”; age=50;} public void display(){ System.out.println(“Name:”+name); System.out.println(“Age:”+age); } } 1. Based on Figure 3, create a class named Child that inherits the Father class. Declare an instance name location (String) for class Child. 2. Define a constructor in class Child and give an appropriate initial values for the instance (name, age, location). 3. Define a method display () in class Child, execute the display ( ) method in superclass using the keyword super. Method display ( ) in class Child should print the information of name, age and location 4. Create other class named Main for the main method and create 2 objects for the 2 classes (Father and Child). Then execute the display ( ) method for Father and Child. Example of the output as in Figure 4: Father's info: Name: Josh Age: 50 Child's info: Name: Christy Age: 20 Location:…
1) Draw a class diagram depicting the below code. class Doctor { void Doctor Details () { System.out.println("Doctor Details..."); } class Surgeon extends Doctor { void Surgeon_Details () { System.out.println("Surgen Detail..."); } } public class Hospital { public static void main(String args[]) { Surgeon s = new Surgeon (); } } } 2) Establish an association between Person class and Book Class given below. public class Person { } s. Doctor Details (); s. Surgeon Details (); } private String name; private int age; public Person (String initialName) { this.name = initialName; this.age = 0; } public void printPerson() { } public String getName() { return this.name; } System.out.println(this.name + age public class Book { private String name; private String publisher; private ArrayList authors; // constructor public ArrayList getAuthors() { return this.authors; } public void addAuthor (Person author) { this.authors.add(author); } + this.age + 11 years");
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public class Base { public void PrintName() { System.out.println("Base"); } static void PrintClass() { System.out.println("ClassBase"); } private void PrintPrivate() { System.out.println("PrintPrivate"); } class Derived extends Base { public void PrintName() { System.out.println("Derived"); } static void PrintClass() { System.out.println("ClassDerived"); } private void PrintPrivate() { System.out.println("PrintDerived"); } public static void main(String[] args) { Base x = new Derived(); Derived y = new Derived(); x.PrintClass(); y.PrintPrivate(); x.PrintName();
Finish the constructor for the KickBall class. public class Ball { public double diameter; public Ball(double diam) { diameter = diam; public class KickBall extends Ball private Color ballColor; public KickBall(double diam, Color ballColor) {
public interface Joy ( public void happySign(); } public class Man implements Joy { public Man () { } public void happySign () { System.out.println("smiles"); } public void sadSign () { } red phot System.out.println("frowns"); a) Joy obj1 = new Man(); obj1.sadSign(); public class Dog implements Joy { public Dog () () public void happySign () { } System.out.println("wags tail"); public class GuardDog extends Dog { public GuardDog () { } public void happySign () { System.out.println("barks"); } We public void angrySign () { } System.out.println("growls"); If the following lines of code appeared in the main method of a driver program, would the program compile and run? (yes or no?) If no, write 1-2 sentences to explain why not. If yes, indicate what the output would be. nafn,