Starting Out With Java Tony Gaddis - Chapter 6

This is a collection of programming statements that specify the fields and methods that a particular type of object may have.

a. class

b. method

c. parameter

d. instance

A class is analogous to a(n) __________.

a. house

b. blueprint

c. drafting table

d. architect

An object is a(n) __________. a. blueprint b. primitive data type c. variable d. instance of a class

This is a class member that holds data. a. method b. instance c. field d. constructor

This key word causes an object to be created in memory. a. create b. new c. object d. construct

This is a method that gets a value from a class’s field, but does not change it. a. accessor b. constructor c. void d. mutator

This is a method that stores a value in a field or in some other way changes the value of a field. a. accessor b. constructor c. void d. mutator

When the value of an item is dependent on other data, and that item is not updated when the other data is changed, what has the value become? a. bitter b. stale c. asynchronous d. moldy

This is a method that is automatically called when an instance of a class is created. a. accessor b. constructor c. void d. mutator

When a local variable has the same name as a field, the local variable’s name does this to the field’s name. a. shadows b. complements c. deletes d. merges with

This is automatically provided for a class if you do not write one yourself. a. accessor method b. default instance c. default constructor d. variable declaration

Two or more methods in a class may have the same name, as long as this is different. a. their return values b. their access specifier c. their parameter lists d. their memory address

The process of matching a method call with the correct method is known as__________. a. matching b. binding c. linking d. connecting

A class’s responsibilities are __________. a. the objects created from the class b. things the class knows c. actions the class performs d. both b and c

True or False: The new operator creates an instance of a class.

True or False: Each instance of a class has its own set of instance fields.

True or False: When you write a constructor for a class, it still has the defaultconstructor that Java automatically provides.

True or False: A class may not have more than one constructor.

True or False: To find the classes needed for an object-oriented application, youidentify all of the verbs in a description of the problem domain.

Find the error in the following class:public class MyClass{ private int x; private double y; public void MyClass(int a, double b) { x = a; y = b; }}

Assume that the following method is a member of a class. Find the error.public void total(int value1, value2, value3){ return value1 + value2 + value3;}

The following statement attempts to create a Rectangle object. Find the error.Rectangle box = new Rectangle;

Find the error in the following class:public class TwoValues{ private int x, y; public TwoValues() { x = 0; } public TwoValues() { x = 0; y = 0; }}

Find the error in the following class:public class FindTheError{ public int square(int number) { return number * number; } public double square(int number) { return number * number; }}

Design a class named Pet, which should have the following fields:• name. The name field holds the name of a pet.• animal. The animal field holds the type of animal that a pet is. Example values are“Dog”, “Cat”, and “Bird”.• age. The age field holds the pet’s age. The Pet class should also have the following methods:• setName. The setName method stores a value in the name field.• setAnimal. The setAnimal method stores a value in the animal field.• setAge. The setAge method stores a value in the age field.• getName. The getName method returns the value of the name field.• getAnimal. The getAnimal method returns the value of the animal field.• getAge. The getAge method returns the value of the age field.a. Draw a UML diagram of the class. Be sure to include notation showing each fieldand method’s access specification and data type. Also include notation showing anymethod parameters and their data types.b. Write the Java code for the Pet class.

Look at the following partial class definition, and then respond to the questions thatfollow it:public class Book{ private String title; private String author; private String publisher; private int copiesSold;}a. Write a constructor for this class. The constructor should accept an argument foreach of the fields.b. Write accessor and mutator methods for each field.c. Draw a UML diagram for the class, including the methods you have written.

Consider the following class declaration:public class Square{ private double sideLength; public double getArea() { return sideLength * sideLength; } public double getSideLength() { return sideLength; }}a. Write a no-arg constructor for this class. It should assign the sideLength field thevalue 0.0.b. Write an overloaded constructor for this class. It should accept an argument that iscopied into the sideLength field.

Look at the following description of a problem domain: The bank offers the following types of accounts to its customers: savings accounts,checking accounts, and money market accounts. Customers are allowed to depositmoney into an account (thereby increasing its balance), withdraw money from anaccount (thereby decreasing its balance), and earn interest on the account. Eachaccount has an interest rate. Assume that you are writing an application that will calculate the amount of interestearned for a bank account.a. Identify the potential classes in this problem domain.b. Refine the list to include only the necessary class or classes for this problem.c. Identify the responsibilities of the class or classes.

What is the difference between a class and an instance of a class?

A contractor uses a blueprint to build a set of identical houses. Are classes analogousto the blueprint or the houses?

What is an accessor method? What is a mutator method?

Is it a good idea to make fields private? Why or why not?

If a class has a private field, what has access to the field?

What is the purpose of the new key word?

Assume a program named MailList.java is stored in the DataBase folder on yourhard drive. The program creates objects of the Customer and Account classes. Describethe steps that the compiler goes through in locating and compiling the Customer andAccount classes.

Why are constructors useful for performing “start-up” operations?

Under what circumstances does Java automatically provide a default constructor fora class?

What do you call a constructor that accepts no arguments?

When the same name is used for two or more methods in the same class, how doesJava tell them apart?

How does method overloading improve the usefulness of a class?