Question 1

Intermediate operations are________; they aren't performed until a terminal operation is invoked. This allows library developers to optimize stream-processing performance.

Accepted Answer

A)  eager 
B)  idle 
C)  lazy 
D)  inactive 
A)  eager 
B)  idle 
C)  lazy 
D)  inactive C

Question 2

Which of the following statements is false?

Accepted Answer

A)  A lambda that receives two ints, x and y, and returns their sum is (int x, int y) -> {return x + y;} 
B)  A lambda's parameter types may be omitted, as in: (x, y) -> {return x + y;}
In which case, the parameter and return types are set to the lambda's default type. 
C)  A lambda with a one-expression body can be written as: (x, y) -> x + y
In this case, the expression's value is implicitly returned. 
D)  When a lambda's parameter list contains only one parameter, the parentheses may be omitted, as in: value -> System.out.printf("%d ", value) 
A)  A lambda that receives two ints, x and y, and returns their sum is (int x, int y) -> {return x + y;} 
B)  A lambda's parameter types may be omitted, as in: (x, y) -> {return x + y;}
In which case, the parameter and return types are set to the lambda's default type. 
C)  A lambda with a one-expression body can be written as: (x, y) -> x + y
In this case, the expression's value is implicitly returned. 
D)  When a lambda's parameter list contains only one parameter, the parentheses may be omitted, as in: value -> System.out.printf("%d ", value) B

Question 3

Which statement in the following sequence of statements about sorting objects by two fields is false?

Accepted Answer

A)  To sort objects by two fields, you create a Comparator that uses two Functions. 
B)  First you call Comparator method comparing to create a Comparator with the first Function. 
C)  On the Comparator for the first field, you call method comparing with the second Function. 
D)  The resulting Comparator compares objects using the first Function then, for objects that are equal, compares them by the second Function. 
A)  To sort objects by two fields, you create a Comparator that uses two Functions. 
B)  First you call Comparator method comparing to create a Comparator with the first Function. 
C)  On the Comparator for the first field, you call method comparing with the second Function. 
D)  The resulting Comparator compares objects using the first Function then, for objects that are equal, compares them by the second Function. C

Question 4

Collectors static method ________ returns a Collector that counts the number of objects in a given classification, rather than collecting them into a List.

Accepted Answer

A)  counter 
B)  count 
C)  counting 
D)  enumerate 
A)  counter 
B)  count 
C)  counting 
D)  enumerate

Question 5

Terminal operations are ________; they perform the requested operation when they are called.

Accepted Answer

A)  immediate 
B)  idle 
C)  lazy 
D)  eager 
A)  immediate 
B)  idle 
C)  lazy 
D)  eager

Question 6

Stream method findFirst is a short-circuiting terminal operation that processes the stream pipeline and terminates processing as soon as the first object from the stream pipeline is found. The method returns a(n) ________ containing the object that was found, if any.

Accepted Answer

A)  Optional 
B)  Discretionary 
C)  Elective 
D)  Extra 
A)  Optional 
B)  Discretionary 
C)  Elective 
D)  Extra

Question 7

Stream mutable reduction operation ________creates an array containing the results of the stream's prior operations.

Accepted Answer

A)  array 
B)  createArray 
C)  toArray 
D)  reduceArray 
A)  array 
B)  createArray 
C)  toArray 
D)  reduceArray

Question 8

By default, method sorted uses ________.

Accepted Answer

A)  ascending order 
B)  the natural order for the stream's element type 
C)  descending order 
D)  the order specified in a command-line argument 
A)  ascending order 
B)  the natural order for the stream's element type 
C)  descending order 
D)  the order specified in a command-line argument

Question 9

Map method ________ performs an operation on each key-value pair.

Accepted Answer

A)  for 
B)  forNext 
C)  forEach 
D)  forAll 
A)  for 
B)  forNext 
C)  forEach 
D)  forAll

Question 10

Which of the following statements is false?

Accepted Answer

A)  Each intermediate operation results in a new stream. 
B)  Each new stream is simply an object representing the processing steps that have been specified to that point in the pipeline. 
C)  Chaining intermediate-operation method calls adds to the set of processing steps to perform on each stream element. The last stream object in the stream pipeline contains all the processing steps to perform on each stream element. 
D)  When you initiate a stream pipeline with a terminal operation, the each processing step is applied for to all the stream elements before the next processing step is applied. 
A)  Each intermediate operation results in a new stream. 
B)  Each new stream is simply an object representing the processing steps that have been specified to that point in the pipeline. 
C)  Chaining intermediate-operation method calls adds to the set of processing steps to perform on each stream element. The last stream object in the stream pipeline contains all the processing steps to perform on each stream element. 
D)  When you initiate a stream pipeline with a terminal operation, the each processing step is applied for to all the stream elements before the next processing step is applied.

Question 11

Collectors static method groupingBy with two arguments receives a Function that classifies the objects in the stream and another Collector (known as the ________ Collector).

Accepted Answer

A)  stream 
B)  downstream 
C)  grouping stream 
D)  upsteam 
A)  stream 
B)  downstream 
C)  grouping stream 
D)  upsteam

Question 12

Prior to Java SE 8, Java supported three programming paradigms. Java SE 8 added ________.

Accepted Answer

A)  procedural programming 
B)  object-oriented programming 
C)  generic programming 
D)  functional programming. 
A)  procedural programming 
B)  object-oriented programming 
C)  generic programming 
D)  functional programming.

Question 13

Stream method ________ maps objects to double values and returns a DoubleStream. The method receives an object that implements the functional interface ToDoubleFunction (package java.util.function).

Accepted Answer

A)  doubleMap 
B)  toDouble 
C)  mapToDouble 
D)  toDoubleStream 
A)  doubleMap 
B)  toDouble 
C)  mapToDouble 
D)  toDoubleStream

Question 14

Class Array's ________ method is used to create a Stream from an array of objects.

Accepted Answer

A)  stream 
B)  arrayToStream 
C)  createStream 
D)  objectToStream 
A)  stream 
B)  arrayToStream 
C)  createStream 
D)  objectToStream

Question 15

Which of the following statements is false?

Accepted Answer

A)  Functional interfaces are also known as single abstract method (SAM) interfaces. 
B)  Package java.util.function contains six basic functional interfaces BinaryOperator, Consumer, Function, Predicate, Supplier and UnaryOperator. 
C)  There are many specialized versions of the six basic functional interfaces for use with int, long and double primitive values. There are also generic customizations of Consumer, Function and Predicate for binary operations-that is, methods that take two arguments. 
D)  All of these statements are true. 
A)  Functional interfaces are also known as single abstract method (SAM) interfaces. 
B)  Package java.util.function contains six basic functional interfaces BinaryOperator, Consumer, Function, Predicate, Supplier and UnaryOperator. 
C)  There are many specialized versions of the six basic functional interfaces for use with int, long and double primitive values. There are also generic customizations of Consumer, Function and Predicate for binary operations-that is, methods that take two arguments. 
D)  All of these statements are true.

Question 16

Map method entrySet returns a Set of Map.Entry objects containing the Map's ________.

Accepted Answer

A)  values 
B)  keys 
C)  index 
D)  key-value pairs 
A)  values 
B)  keys 
C)  index 
D)  key-value pairs

Question 17

Which of the following statements is false?

Accepted Answer

A)  Functional interfaces must contain only one method and that method must be abstract. 
B)  When a class implements an interface with default methods and does not override them, the class inherits the default methods' implementations. An interface's designer can now evolve an interface by adding new default and static methods without breaking existing code that implements the interface. 
C)  If one class inherits the same default method from two interfaces, the class must override that method; otherwise, the compiler will generate a compilation error. 
D)  You can create your own functional interfaces by ensuring that each contains only one abstract method and zero or more default or static methods. 
A)  Functional interfaces must contain only one method and that method must be abstract. 
B)  When a class implements an interface with default methods and does not override them, the class inherits the default methods' implementations. An interface's designer can now evolve an interface by adding new default and static methods without breaking existing code that implements the interface. 
C)  If one class inherits the same default method from two interfaces, the class must override that method; otherwise, the compiler will generate a compilation error. 
D)  You can create your own functional interfaces by ensuring that each contains only one abstract method and zero or more default or static methods.

Question 18

The intermediate Stream operation ________ results in a stream containing only the unique elements.

Accepted Answer

A)  distinct 
B)  map 
C)  filter 
D)  limit 
A)  distinct 
B)  map 
C)  filter 
D)  limit

Question 19

Which of the following statements is false?

Accepted Answer

A)  You filter elements to produce a stream of intermediate results that match a predicate. 
B)  IntStream method filter receives an object that method that takes one parameter and returns a boolean result. 
C)  If the result of calling filter's argument is true for a given element, that element is included in the resulting stream. 
D)  All of the above statements are true. 
A)  You filter elements to produce a stream of intermediate results that match a predicate. 
B)  IntStream method filter receives an object that method that takes one parameter and returns a boolean result. 
C)  If the result of calling filter's argument is true for a given element, that element is included in the resulting stream. 
D)  All of the above statements are true.

Question 20

________ is a method reference for an instance method of a class. It creates a one-parameter lambda that invokes the instance method on the lambda's argument and returns the method's result.

Accepted Answer

A)  Math::sqrt 
B)  System.out::println 
C)  TreeMap::new 
D)  String::toUpperCase 
A)  Math::sqrt 
B)  System.out::println 
C)  TreeMap::new 
D)  String::toUpperCase

Exam 17: Lambdas and Streams

Intermediate operations are________; they aren't performed until a terminal operation is invoked. This allows library developers to optimize stream-processing performance.

Which of the following statements is false?

Which statement in the following sequence of statements about sorting objects by two fields is false?

Collectors static method ________ returns a Collector that counts the number of objects in a given classification, rather than collecting them into a List.

Terminal operations are ________; they perform the requested operation when they are called.

Stream method findFirst is a short-circuiting terminal operation that processes the stream pipeline and terminates processing as soon as the first object from the stream pipeline is found. The method returns a(n) ________ containing the object that was found, if any.

Stream mutable reduction operation ________creates an array containing the results of the stream's prior operations.

By default, method sorted uses ________.

Map method ________ performs an operation on each key-value pair.

Which of the following statements is false?

Collectors static method groupingBy with two arguments receives a Function that classifies the objects in the stream and another Collector (known as the ________ Collector).

Prior to Java SE 8, Java supported three programming paradigms. Java SE 8 added ________.

Stream method ________ maps objects to double values and returns a DoubleStream. The method receives an object that implements the functional interface ToDoubleFunction (package java.util.function).

Class Array's ________ method is used to create a Stream from an array of objects.

Which of the following statements is false?

Map method entrySet returns a Set of Map.Entry objects containing the Map's ________.

Which of the following statements is false?

The intermediate Stream operation ________ results in a stream containing only the unique elements.

Which of the following statements is false?

________ is a method reference for an instance method of a class. It creates a one-parameter lambda that invokes the instance method on the lambda's argument and returns the method's result.

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

Generic Collections

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