ITP 120 Chapter 6
Which symbol indicates that a member is public in a UML diagram?
+ (plus)
Which symbol indicates that a member is private a UML diagram?
- (minus)
Given the following code, what will be the value of finalAmount when it is displayed? public class Order { private int orderNum; private double orderAmount; private double orderDiscount; public Order(int orderNumber, double orderAmt, double orderDisc) { orderNum = orderNumber; orderAmount = orderAmt; orderDiscount = orderDisc; } public double finalOrderTotal() { return orderAmount - orderAmount * orderDiscount; } } public class CustomerOrder { public static void main(String[] args) { Order order; int orderNumber = 1234; double orderAmt = 580.00; double orderDisc = .1; order = new Order(orderNumber, orderAmt, orderDisc); double finalAmount = order.finalOrderTotal(); System.out.printf("Final order amount = $%,.2f\n", finalAmount); } }
522.00
A method that gets a value from a class's field but does not change it is known as a mutator method.
FALSE
Instance methods should be declared static.
FALSE
The public access specifier for a field indicates that the field may not be accessed by statements outside the class
FALSE
The term "default constructor" is applied to the first constructor written by the author of the class.
FALSE
When a local variable in an instance method has the same name as an instance field, the instance field hides the local variable
FALSE
You should not define a class that is dependent on the values of other class fields _________
In order to avoid having stale data
Java allows you to create objects of the __________ class in the same way you would create primitive variables.
String
Which of the following statements will create a reference, str, to the String "Hello, World"?
String str = "Hello, World";
A class is not an object. It is a description of an object
TRUE
A constructor is a method that is automatically called when an object is created
TRUE
A method that stores a value in a class's field or in some other way changes the value of a field is known as a mutator method
TRUE
An access specifier indicates how a class may be accessed.
TRUE
An object can store data.
TRUE
Instance methods do not have the key word static in their headers.
TRUE
Shadowing is the term used to describe where the field name is hidden by the name of a local or parameter variable.
TRUE
The java.lang package is automatically imported into all Java programs
TRUE
The term "no-arg constructor" is applied to any constructor that does not accept arguments
TRUE
When an object is passed as an argument to a method, the object's address is passed into the method's parameter variable
TRUE
For the following code, which statement is not true? public class Sphere { private double radius; public double x; private double y; private double z; }
The z field is available to code written outside the Sphere class.
Given the following code, what will be the value of finalAmount when it is displayed? public class Order { private int orderNum; private double orderAmount; private double orderDiscount; public Order(int orderNumber, double orderAmt, double orderDisc) { orderNum = orderNumber; orderAmount = orderAmt; orderDiscount = orderDisc; } public int getOrderAmount() { return orderAmount; } public int getOrderDisc() { return orderDisc; } } public class CustomerOrder { public static void main(String[] args) { int ordNum = 1234; double ordAmount = 580.00; double discountPer = .1; Order order; double finalAmount = order.getOrderAmount() — order.getOrderAmount() * order.getOrderDisc(); System.out.printf("Final order amount = $%,.2f\n", finalAmount); } }
There is no value because the object, order, has not been created.
What does the following UML diagram entry mean? + setHeight(h : double) : void
a public method with a parameter of data type double that does not return a value
The following statement is an example of __________. import java.util.*;
a wildcard import statement
The following statement is an example of __________. import java.util.Scanner;
an explicit import statement
A class's responsibilities include
both of these -the things a class is responsible for knowing -the things a class is responsible for doing
After the header, the body of the method appears inside a set of _________
braces, { }
One or more objects may be created from a(n) ________
class
A(n) __________ can be thought of as a blueprint that can be used to create a type of __________
class, object
It is common practice in object-oriented programming to make all of a class's _________
fields private
A class specifies the __________ and __________ that a particular type of object has
fields, methods
A constructor ________
has the same name as the class
Overloading means that multiple methods in the same class _______
have the same name but different parameter lists
Another term for an object of a class is a(n) ________
instance
When an object is created, the attributes associated with the object are called __________
instance fields
Methods that operate on an object's fields are called _______
instance methods
Methods that operate on an object's fields are called ________
instance methods
The __________ package is automatically imported into all Java programs.
java.lang
A reference variable stores a(n) _______
memory address
Class objects normally have __________ that perform useful operations on their data, but primitive variables do not.
methods
Most of the programming languages used today are ________
object-oriented
A group of related classes is called a(n) ________
package
A constructor is a method that ________
performs initialization or setup operations
When you work with a __________, you are using a storage location that holds a piece of data.
primitive variable
Instance methods do not have the __________ keyword in their headers.
static
Which of the following is not involved in identifying the classes to be used when developing an object-oriented application?
the code
The scope of a public instance field is ________
the instance methods and methods outside the class
The scope of a private instance field is _______
the instance methods of the same class
A UML diagram does not contain ________
the object names
When an object is passed as an argument to a method, what is passed into the method's parameter variable?
the object's memory address
To indicate the data type of a variable in a UML diagram, you enter _____
the variable name followed by a colon and the data type
Two or more methods in a class may have the same name as long
they have different parameter lists
Data hiding (which means that critical data stored inside the object is protected from code outside the object) is accomplished in Java by __________
using the private access specifier on the class fields
For the following code, which statement is not true? public class Circle { private double radius; public double x; private double y; }
The y field is available to code written outside the Circle class
