You are given a super class called People and a sub-class (derived class) called Engineer. The sub-class (derived class) has a method called update(), but the super class does not have update() method. Which of the following is the correct use of update method? O a. Engineer a = new People(); ....; a.update(); O b. People a = new Engineer(); ....; a.update(); O. People a = new People(); ...; a.update(); O d. Engineer a = new Engineer(); ..; a.update();

You are given a super class called People and a sub-class (derived class) called Engineer. The sub-class (derived class) has a method called update(), but the super class does not have update() method. Which of the following is the correct use of update method? O a. Engineer a = new People(); ....; a.update(); O b. People a = new Engineer(); ....; a.update(); O. People a = new People(); ...; a.update(); O d. Engineer a = new Engineer(); ..; a.update();

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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Consider the above scenario, where Billing class has composition relationship with Doctor having private instance variables (docName, docID and docFee) and a public getDocID() method, Patient having private instance variables (pName, pID, pDisease), Medicine having private instance variables (medID, medName, medQty, medPrice), and MedicalTest having private instance variables (testID, testName, testPrice). In addition, each class shall have toString method to display its object state. Also define getDocInfo method in Billing class that shall return the doctor. Implement getPaymentAmount() method in Billing class that shall return the total billing amount that includes doctor fee, medicine cost and medical tests fee. Considering the above scenario, write code that shall perform the following in the driver/test class: Get an amount from user. Traverse the ArrayList<Billing> using enhanced for loop. Print the billing details of those bills having total billing amount greater or…
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Q# Which of the following might have only method signatures? Group of answer choices 1. An interface 2. An abstract class and a concrete class 3. An abstract class 4. An interface and an abstract class 5. None of these, they all require the implementation. 6. A concrete class
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Which of the following statements are false? (All that are not true). Group of answer choices A reference of type super class can refer to an instance of type subclass. A reference of type subclass can refer to an instance of type super class. A method in the super class can be overridden two different ways in two different subclasses. A method in the super class can be overridden by changing its signature in the subclass.
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