Question 1

Which of the following statements is false?

Accepted Answer

A)  Interface IntPredicate's default method and performs a logical AND operation with short-circuit evaluation between the IntPredicate on which it's called and its IntPredicate argument. 
B)  Interface IntPredicate's default method invert reverses the boolean value of the IntPredicate on which it's called. 
C)  Interface IntPredicate default method or performs a logical OR operation with short-circuit evaluation between the IntPredicate on which it's called and its IntPredicate argument. 
D)  You can use the interface IntPredicate default methods to compose more complex conditions.

Question 2

Which of the following statements is false?

Accepted Answer

A)  Some event-listener interfaces are functional interfaces. 
B)  For such interfaces as mentioned in (a), you can implement event handlers with lambdas. 
C)  For a simple event handler, a lambda significantly reduces the amount of code you need to write. 
D)  All of the above are true.

Question 3

IntStream method ________ (a terminal operation) performs a task on each stream element.

Accepted Answer

A)  for 
B)  forEach 
C)  forElement 
D)  None of the above.

Question 4

________ is an intermediate operation that transforms a stream's elements to new values and produces a stream containing the resulting (possibly different type) elements.

Accepted Answer

A)  Transforming 
B)  Converting 
C)  Mapping 
D)  Translating

Question 5

You can define your own reductions for an IntStream by calling its ________ method. The first argument is a value that helps you begin the reduction operation and the second argument is an object that implements the IntBinaryOperator functional interface.

Accepted Answer

A)  reduction. 
B)  lessen 
C)  trim 
D)  reduce

Question 6

Which of the following statements is false?

Accepted Answer

A)  Files method lines creates a String containing the lines of text from a file. 
B)  Stream method flatMap receives a Function that maps an object into a stream-e.g., a line of text into words. 
C)  Pattern method splitAsStream uses a regular expression to tokenize a String. 
D)  Collectors method groupingBy with three arguments receives a classifier, a Map factory and a downstream Collector.

Question 7

Intermediate Stream operation ________ results in a stream with the specified number of elements from the beginning of the original stream.

Accepted Answer

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

Question 8

Which of the following statements is false?

Accepted Answer

A)  Streams are objects that implement interface Stream (from the package java.util.stream) and enable you to perform functional programming tasks. 
B)  Streams move elements through a sequence of processing steps-known as a stream pipeline-that begins with a data source, performs various intermediate operations on the data source's elements and ends with a terminal operation. 
C)  A stream pipeline is formed by chaining method calls. 
D)  An advantage of streams over collections is that streams have their own storage, so once a stream is processed, it can be reused, because it maintains a copy of the original data source.

Question 9

Which of the following statements is false?

Accepted Answer

A)  Lambda expressions can be used anywhere functional interfaces are expected. 
B)  A lambda consists of a parameter list followed by the arrow token and a body, as in: [parameterList] -> {statements} 
C) Method references are specialized shorthand forms of lambdas. 
D)  Each of the above statements is true.

Question 10

Which of the following statements is false?

Accepted Answer

A)  A method reference of the form objectName::instanceMethodName is a bound instance method reference. 
B)  A method reference of the form ClassName::staticMethodName is a static method reference. 
C)  Collectors method joining is a collector that creates a concatenated String representation of the stream's elements, appending each element to the String separated from the previous element by the joining method's argument. 
D)  All of the above statements are true.

Question 11

You can declare that an interface is a functional interface by preceding it with the @FunctionalInterface annotation. The compiler will then ensure that the interface contains ________; otherwise, it'll generate a compilation error.

Accepted Answer

A)  no abstract methods 
B)  all abstract methods 
C)  only one abstract method 
D)  one or more abstract methods.

Question 12

The basic generic functional interface ________ in package java.util.function contains method get that takes no arguments and produces a value of type T. Often used to create a collection object in which a stream operation's results are placed.

Accepted Answer

A) Consumer B) Function C) Supplier D) BinaryOperator

Question 13

Functional interface Comparator's default method ________ reverses an existing Comparator's ordering.

Accepted Answer

A)  invert 
B)  descending 
C)  reversed 
D)  downward

Question 14

The basic generic functional interface ________ in package java.util.function contains method get that takes no arguments and returns a value of type T.

Accepted Answer

A) UnaryOperator B) Function C) Supplier D) BinaryOperator

Question 15

Collectors static method groupingBy with one argument receives a Function that classifies objects in the stream-the values returned by this function are used as the keys in a Map. The corresponding values, by default, are ________ containing the stream elements in a given category.

Accepted Answer

A)  Lists 
B)  Arrays 
C)  Strings 
D)  Collectors

Question 16

Which of the following statements is false?

Accepted Answer

A)  SecureRandom method ints with two int arguments creates an IntStream for an infinite stream of random int values in the range starting with the first argument and up to, but not including, the second. 
B)  SecureRandom method ints with a long and two int arguments creates an IntStream with the specified number of random int values in the range starting with the first argument and up to, but not including, the second. 
C)  To convert an IntStream to a Stream<Integer> call IntStream method toStream. 
D)  Function static method identity creates a Function that simply returns its argument.

Question 17

Stream method ________ eliminates duplicate objects in a stream.

Accepted Answer

A)  distinct 
B)  discrete 
C)  unique 
D)  different

Question 18

Which of the following statements is false?

Accepted Answer

A)  The parameter names and variable names that you use in lambdas cannot be the same as any other local variables in the lambda's lexical scope; otherwise, a compilation error occurs. 
B)  Lambdas may use only final local variables. 
C)  A lambda that refers to a local variable in the enclosing lexical scope is known as a capturing lambda. 
D)  All of the above statements are true.

Question 19

The type of a lambda is the type of the ________ that the lambda implements.

Accepted Answer

A)  anonymous class 
B)  functional interface 
C)  stream 
D)  collection

Question 20

The intermediate Stream operation ________ results in a stream containing only the elements that satisfy a condition.

Accepted Answer

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

Exam 17: Lambdas and Streams

Which of the following statements is false?

Which of the following statements is false?

IntStream method ________ (a terminal operation) performs a task on each stream element.

________ is an intermediate operation that transforms a stream's elements to new values and produces a stream containing the resulting (possibly different type) elements.

You can define your own reductions for an IntStream by calling its ________ method. The first argument is a value that helps you begin the reduction operation and the second argument is an object that implements the IntBinaryOperator functional interface.

Which of the following statements is false?

Intermediate Stream operation ________ results in a stream with the specified number of elements from the beginning of the original stream.

Which of the following statements is false?

Which of the following statements is false?

Which of the following statements is false?

You can declare that an interface is a functional interface by preceding it with the @FunctionalInterface annotation. The compiler will then ensure that the interface contains ________; otherwise, it'll generate a compilation error.

The basic generic functional interface ________ in package java.util.function contains method get that takes no arguments and produces a value of type T. Often used to create a collection object in which a stream operation's results are placed.

Functional interface Comparator's default method ________ reverses an existing Comparator's ordering.

The basic generic functional interface ________ in package java.util.function contains method get that takes no arguments and returns a value of type T.

Collectors static method groupingBy with one argument receives a Function that classifies objects in the stream-the values returned by this function are used as the keys in a Map. The corresponding values, by default, are ________ containing the stream elements in a given category.

Which of the following statements is false?

Stream method ________ eliminates duplicate objects in a stream.

Which of the following statements is false?

The type of a lambda is the type of the ________ that the lambda implements.

The intermediate Stream operation ________ results in a stream containing only the elements that satisfy a condition.