Question 1

Maps allocate keys to values and cannot contain duplicate keys, i.e., the key-to-value mapping is a __________ mapping.

Accepted Answer

A)  many-to-many. 
B)  many-to-one. 
C)  one-to-many. 
D)  one-to-one. 
A)  many-to-many. 
B)  many-to-one. 
C)  one-to-many. 
D)  one-to-one.

Question 2

The collections framework provides various __________ collection interfaces from which the programmer can quickly "flesh out" complete customized implementations.

Accepted Answer

A)  abstract. 
B)  concrete. 
C)  structured. 
D)  unstructured. 
A)  abstract. 
B)  concrete. 
C)  structured. 
D)  unstructured.

Question 3

Which statement about hashing is false?

Accepted Answer

A)  Hashing facilitates high-speed storing and retrieval of data. 
B)  Two different data items can hash to the same cell; this is called a collision. 
C)  A load factor of 0.5 usually results in good hashing performance, but less efficient utilization of memory. 
D)  A load factor of 1.0 usually results in good hashing performance, but less efficient utilization of memory. 
A)  Hashing facilitates high-speed storing and retrieval of data. 
B)  Two different data items can hash to the same cell; this is called a collision. 
C)  A load factor of 0.5 usually results in good hashing performance, but less efficient utilization of memory. 
D)  A load factor of 1.0 usually results in good hashing performance, but less efficient utilization of memory.

Question 4

Java supports type inferencing with the <> notation in statements that declare and create generic type variables and objects. For example, the following line: List list = new ArrayList(); Can be written as:

Accepted Answer

A) List<> list = new ArrayList<>(); B) List<> list = new ArrayList(); C) List list = new ArrayList<>(); D) List list = new ArrayList(); A) List<> list = new ArrayList<>(); B) List<> list = new ArrayList(); C) List list = new ArrayList<>(); D) List list = new ArrayList();

Question 5

Which of the following performs a boxing conversion?

Accepted Answer

A)  int x = 7; 
B)  Integer x = 7; 
C)  Neither of the above. 
D)  Both of the above. 
A)  int x = 7; 
B)  Integer x = 7; 
C)  Neither of the above. 
D)  Both of the above.

Question 6

Which statement is false?

Accepted Answer

A)  All built-in collections are synchronized. 
B)  Concurrent access to a Collection by multiple threads could cause indeterminate results or fatal errors. 
C)  To prevent potential threading problems, synchronization wrappers are used around collection classes that might be accessed by multiple threads. 
D)  A synchronization wrapper class receives method calls, adds some functionality for thread safety and then delegates the calls to the wrapped class. 
A)  All built-in collections are synchronized. 
B)  Concurrent access to a Collection by multiple threads could cause indeterminate results or fatal errors. 
C)  To prevent potential threading problems, synchronization wrappers are used around collection classes that might be accessed by multiple threads. 
D)  A synchronization wrapper class receives method calls, adds some functionality for thread safety and then delegates the calls to the wrapped class.

Question 7

Collections method __________ returns true if two Collections have no elements in common.

Accepted Answer

A)  shuffle. 
B)  contains. 
C)  hasCommon. 
D)  disjoint. 
A)  shuffle. 
B)  contains. 
C)  hasCommon. 
D)  disjoint.

Question 8

Which statement is false?

Accepted Answer

A)  Each primitive type has a corresponding type-wrapper class. 
B)  The type-wrapper classes enable you to manipulate primitive-type values as objects. 
C)  Type-wrapper classes are final, so you cannot extend them. 
D)  The methods for primitive types correspond to the methods for the corresponding type-wrapper classes. 
A)  Each primitive type has a corresponding type-wrapper class. 
B)  The type-wrapper classes enable you to manipulate primitive-type values as objects. 
C)  Type-wrapper classes are final, so you cannot extend them. 
D)  The methods for primitive types correspond to the methods for the corresponding type-wrapper classes.

Question 9

Iterator method __________ determines whether the Collection contains more elements.

Accepted Answer

A)  hasNext. 
B)  next. 
C)  contains. 
D)  containsNext. 
A)  hasNext. 
B)  next. 
C)  contains. 
D)  containsNext.

Question 10

Which statement is false?

Accepted Answer

A)  The Collections API provides a set of public static methods for converting collections to unmodifiable versions. 
B)  Unmodifable wrappers throw ModificationExceptions if attempts are made to modify the collection. 
C)  You can use an unmodifiable wrapper to create a collection that offers read-only access to others while allowing read-write access to yourself. 
D)  You can create the kind of collection mentioned in part (c) simply by giving others a reference to the unmodifiable wrapper while you also retain a reference to the wrapped collection itself. 
A)  The Collections API provides a set of public static methods for converting collections to unmodifiable versions. 
B)  Unmodifable wrappers throw ModificationExceptions if attempts are made to modify the collection. 
C)  You can use an unmodifiable wrapper to create a collection that offers read-only access to others while allowing read-write access to yourself. 
D)  You can create the kind of collection mentioned in part (c) simply by giving others a reference to the unmodifiable wrapper while you also retain a reference to the wrapped collection itself.

Question 11

To find the smallest and largest element of a Collection, use Collections methods _________ and __________.

Accepted Answer

A)  least, greatest. 
B)  smallest, largest. 
C)  first, last. 
D)  min, max. 
A)  least, greatest. 
B)  smallest, largest. 
C)  first, last. 
D)  min, max.

Question 12

If the desired Object is not found, binarySearch returns __________.

Accepted Answer

A)  a positive value 
B)  zero 
C)  a negative value 
D)  an ObjectNotFoundError. 
A)  a positive value 
B)  zero 
C)  a negative value 
D)  an ObjectNotFoundError.

Question 13

Which statement is false?

Accepted Answer

A)  A collection is an object that can hold references to other objects. 
B)  The collection interfaces declare the operations that can be performed on each type of collection. 
C)  Collections discourage software reuse because they are non-portable. 
D)  Collections are carefully constructed for rapid execution and efficient use of memory. 
A)  A collection is an object that can hold references to other objects. 
B)  The collection interfaces declare the operations that can be performed on each type of collection. 
C)  Collections discourage software reuse because they are non-portable. 
D)  Collections are carefully constructed for rapid execution and efficient use of memory.

Question 14

Map method ________ is used to determine whether a map contains a mapping for the specified key.

Accepted Answer

A)  containsKey 
B)  hasKey 
C)  containsMapping 
D)  hasMapping 
A)  containsKey 
B)  hasKey 
C)  containsMapping 
D)  hasMapping

Question 15

Collections method ___________ returns a Comparator object that orders the collection's elements in reverse order.

Accepted Answer

A)  rotate. 
B)  shuffle. 
C)  reverse. 
D)  reverseOrder. 
A)  rotate. 
B)  shuffle. 
C)  reverse. 
D)  reverseOrder.

Question 16

Class Collections provides algorithms for reversing, filling and copying ________.

Accepted Answer

A)  Lists. 
B)  Collections. 
C)  Arrays. 
D)  Stacks. 
A)  Lists. 
B)  Collections. 
C)  Arrays. 
D)  Stacks.

Exam 16: Generic Collections

Maps allocate keys to values and cannot contain duplicate keys, i.e., the key-to-value mapping is a __________ mapping.

The collections framework provides various __________ collection interfaces from which the programmer can quickly "flesh out" complete customized implementations.

Which statement about hashing is false?

Java supports type inferencing with the <> notation in statements that declare and create generic type variables and objects. For example, the following line: List<String> list = new ArrayList<String>(); Can be written as:

Which of the following performs a boxing conversion?

Which statement is false?

Collections method __________ returns true if two Collections have no elements in common.

Which statement is false?

Iterator method __________ determines whether the Collection contains more elements.

Which statement is false?

To find the smallest and largest element of a Collection, use Collections methods _________ and __________.

If the desired Object is not found, binarySearch returns __________.

Which statement is false?

Map method ________ is used to determine whether a map contains a mapping for the specified key.

Collections method ___________ returns a Comparator object that orders the collection's elements in reverse order.

Class Collections provides algorithms for reversing, filling and copying ________.

Introduction to Computers, the Internet and Java

Introduction to Java Applications; Inputoutput and Operators

Introduction to Classes, Objects, Methods and Strings

Control Statements: Assignment, and Operators

Control Statements: Logical Operators

Methods: a Deeper Look

Arrays and Arraylists

Classes and Objects: a Deeper Look

Object-Oriented Programming: Inheritance

Object-Oriented Programming: Polymorphism and Interfaces

Exception Handling: a Deeper Look

Javafx Graphical User Interfaces

Javafx Gui

Strings, Characters and Regular Expressions

Files, Inputoutput Streams, Nio and Xml Serialization

Lambdas and Streams

Recursion

Searching, Sorting and Big O

Generic Classes and Methods: a Deeper Look

Custom Generic Data Structures

Concurrency

Accessing Databases With Jdbc

Swing Gui Components

Graphics and Java 2d

Networking

Java Persistence Api Jpa

Javaserver Faces Web Apps

Javaserver Faces Web Apps

Swing Gui Components

Filters

To find the smallest and largest element of a Collection, use Collections methods _ and __.