Question 1

Which of the following statements is true?

Accepted Answer

A) Methods and instance variables can both be either public or private. 
B) Information hiding is achieved by restricting access to class members via keyword public. 
C) The private members of a class are directly accessible to the clients of a class. 
D) None of the above is true. 
A) Methods and instance variables can both be either public or private. 
B) Information hiding is achieved by restricting access to class members via keyword public. 
C) The private members of a class are directly accessible to the clients of a class. 
D) None of the above is true. A

Question 2

Composition is sometimes referred to as a(n)________.

Accepted Answer

A) is-a relationship 
B) has-a relationship 
C) many-to-one relationship 
D) one-to-many relationship 
A) is-a relationship 
B) has-a relationship 
C) many-to-one relationship 
D) one-to-many relationship B

Question 3

Having a this reference allows:

Accepted Answer

A) a method to refer explicitly to the instance variables and other methods of the object on which the method was called. 
B) a method to refer implicitly to the instance variables and other methods of the object on which the method was called. 
C) an object to reference itself. 
D) All of the above. 
A) a method to refer explicitly to the instance variables and other methods of the object on which the method was called. 
B) a method to refer implicitly to the instance variables and other methods of the object on which the method was called. 
C) an object to reference itself. 
D) All of the above. D

Question 4

Which statement is false?

Accepted Answer

A) The actual data representation used within the class is of no concern to the class's clients. 
B) Clients generally care about what the class does but not how the class does it. 
C) Clients are usually involved in a class's implementation. 
D) Hiding the implementation reduces the possibility that clients will become dependent on class-implementation details. 
A) The actual data representation used within the class is of no concern to the class's clients. 
B) Clients generally care about what the class does but not how the class does it. 
C) Clients are usually involved in a class's implementation. 
D) Hiding the implementation reduces the possibility that clients will become dependent on class-implementation details.

Question 5

When must a program explicitly use the this reference?

Accepted Answer

A) Accessing a private variable. 
B) Accessing a public variable. 
C) Accessing a local variable. 
D) Accessing an instance variable that is shadowed by a local variable. 
A) Accessing a private variable. 
B) Accessing a public variable. 
C) Accessing a local variable. 
D) Accessing an instance variable that is shadowed by a local variable.

Question 6

The _________ of a class are also called the public services or the public interface that the class provides to its clients.

Accepted Answer

A) public constructors. 
B) public instance variables. 
C) public methods. 
D) All of the above. 
A) public constructors. 
B) public instance variables. 
C) public methods. 
D) All of the above.

Question 7

A constructor cannot:

Accepted Answer

A) be overloaded. 
B) initialize variables to their defaults. 
C) specify return types or return values. 
D) have the same name as the class. 
A) be overloaded. 
B) initialize variables to their defaults. 
C) specify return types or return values. 
D) have the same name as the class.

Question 8

Which of the following statements is false?

Accepted Answer

A) An application that requires precise floating-point calculations such as those in financial applications should use class BigDecimal from package java.math. 
B) We use class NumberFormat for formatting numeric values as locale-specific strings. 
C) In the U.S,locale,the value 15467.82 would be formatted as "15,467.82",whereas in many European locales it would be formatted as "15.467,56". 
D) The BigDecimal method format receives a double argument and returns a BigDecimal object that represents the exact value specied. 
A) An application that requires precise floating-point calculations such as those in financial applications should use class BigDecimal from package java.math. 
B) We use class NumberFormat for formatting numeric values as locale-specific strings. 
C) In the U.S,locale,the value 15467.82 would be formatted as "15,467.82",whereas in many European locales it would be formatted as "15.467,56". 
D) The BigDecimal method format receives a double argument and returns a BigDecimal object that represents the exact value specied.

Question 9

When no access modifier is specified for a method or variable,the method or variable:

Accepted Answer

A) Is public. 
B) Is private. 
C) Has package access. 
D) Is static. 
A) Is public. 
B) Is private. 
C) Has package access. 
D) Is static.

Question 10

The static method ________ of class String returns a formatted String.

Accepted Answer

A) printf. 
B) format. 
C) formatString. 
D) toFormatedString. 
A) printf. 
B) format. 
C) formatString. 
D) toFormatedString.

Question 11

Static class variables:

Accepted Answer

A) are final. 
B) are public. 
C) are private. 
D) are shared by all objects of a class. 
A) are final. 
B) are public. 
C) are private. 
D) are shared by all objects of a class.

Question 12

A programmer-defined constructor that has no arguments is called a(n)________.

Accepted Answer

A) empty constructor. 
B) no-argument constructor. 
C) default constructor. 
D) null constructor. 
A) empty constructor. 
B) no-argument constructor. 
C) default constructor. 
D) null constructor.

Question 13

Which statement is false?

Accepted Answer

A) An enum declaration is a comma-separated list of enum constants and may optionally include other components of traditional classes,such as constructors,fields and methods. 
B) Any attempt to create an object of an enum type with operator new results in a compilation error. 
C) An enum constructor cannot be overloaded. 
D) enum constants are implicitly final and static. 
A) An enum declaration is a comma-separated list of enum constants and may optionally include other components of traditional classes,such as constructors,fields and methods. 
B) Any attempt to create an object of an enum type with operator new results in a compilation error. 
C) An enum constructor cannot be overloaded. 
D) enum constants are implicitly final and static.

Question 14

What happens when this is used in a constructor's body to call another constructor of the same class if that call is not the first statement in the constructor?

Accepted Answer

A) A compilation error occurs. 
B) A runtime error occurs. 
C) A logic error occurs. 
D) Nothing happens.The program compiles and runs. 
A) A compilation error occurs. 
B) A runtime error occurs. 
C) A logic error occurs. 
D) Nothing happens.The program compiles and runs.

Question 15

BigDecimal gives you control over how values are rounded.By default:

Accepted Answer

A) all calculations are approximate and no rounding occurs. 
B) all calculations are approximate and rounding occurs. 
C) all calculations are exact and no rounding occurs. 
D) all calculations are exact and rounding occurs. 
A) all calculations are approximate and no rounding occurs. 
B) all calculations are approximate and rounding occurs. 
C) all calculations are exact and no rounding occurs. 
D) all calculations are exact and rounding occurs.

Question 16

Which statement is false?

Accepted Answer

A) The compiler always creates a default constructor for a class. 
B) If a class's constructors all require arguments and a program attempts to call a no-argument constructor to initialize an object of the class,a compilation error occurs. 
C) A constructor can be called with no arguments only if the class does not have any constructors or if the class has a public no-argument constructor. 
D) None of the above. 
A) The compiler always creates a default constructor for a class. 
B) If a class's constructors all require arguments and a program attempts to call a no-argument constructor to initialize an object of the class,a compilation error occurs. 
C) A constructor can be called with no arguments only if the class does not have any constructors or if the class has a public no-argument constructor. 
D) None of the above.

Question 17

Which of the following is false?

Accepted Answer

A) Method finalize does not take parameters and has return type void. 
B) Memory leaks using Java are rare because of automatic garbage collection. 
C) Objects are marked for garbage collection by method finalize. 
D) The garbage collector reclaims unused memory. 
A) Method finalize does not take parameters and has return type void. 
B) Memory leaks using Java are rare because of automatic garbage collection. 
C) Objects are marked for garbage collection by method finalize. 
D) The garbage collector reclaims unused memory.

Question 18

Which of the following statements is false?

Accepted Answer

A) If a program uses multiple classes from the same package,these classes can access each other's package access members directly through references to objects of the appropriate classes,or in the case of static members,through the class name. 
B) Package access is rarely used. 
C) Classes in the same source file are part of the same package. 
D) Use the access modifier package to give a method or variable package access. 
A) If a program uses multiple classes from the same package,these classes can access each other's package access members directly through references to objects of the appropriate classes,or in the case of static members,through the class name. 
B) Package access is rarely used. 
C) Classes in the same source file are part of the same package. 
D) Use the access modifier package to give a method or variable package access.

Question 19

Instance variables declared final do not or cannot:

Accepted Answer

A) Cause syntax errors if used as a left-hand value. 
B) Be initialized. 
C) Be modified after they are initialized. 
D) None of the above. 
A) Cause syntax errors if used as a left-hand value. 
B) Be initialized. 
C) Be modified after they are initialized. 
D) None of the above.

Question 20

Which method returns an array of the enum's constants?

Accepted Answer

A) values. 
B) getValues. 
C) constants. 
D) getConstants. 
A) values. 
B) getValues. 
C) constants. 
D) getConstants.

Exam 8: Classes and Objects: a Deeper Look

Which of the following statements is true?

Composition is sometimes referred to as a(n)________.

Having a this reference allows:

Which statement is false?

When must a program explicitly use the this reference?

The _________ of a class are also called the public services or the public interface that the class provides to its clients.

A constructor cannot:

Which of the following statements is false?

When no access modifier is specified for a method or variable,the method or variable:

The static method ________ of class String returns a formatted String.

Static class variables:

A programmer-defined constructor that has no arguments is called a(n)________.

Which statement is false?

What happens when this is used in a constructor's body to call another constructor of the same class if that call is not the first statement in the constructor?

BigDecimal gives you control over how values are rounded.By default:

Which statement is false?

Which of the following is false?

Which of the following statements is false?

Instance variables declared final do not or cannot:

Which method returns an array of the enum's constants?

Introduction to Computers and Java

Introduction to Java Applications

Introduction to Classes and Objects

Control Statements: Part 1

Control Statements: Part 2

Methods: a Deeper Look

Arrays and Arraylists

Object Oriented Programming: Inheritance

Object-Oriented Programming: Polymorphism

Exception Handling

Gui Components: Part 1

Graphics and Java 2D

Strings

Files,streams and Object Serialization

Generic Collections

Lambdas

Recursion

Searching, Sorting and Big O

Generic Classes and Methods

Custom Generic Data Structures

Concurrency

Accessing Databases With Jdbc

JavaFX

Filters