Question 1

Which of the following statements is false?

Accepted Answer

All the statements provided are true. Functional interfaces indeed are known as single abstract method interfaces, the java.util.function package contains the mentioned basic functional interfaces, and there are specialized versions of these interfaces for primitive types and binary operations.

Question 2

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

Question 3

Class IntStream provides terminal operations for common stream ________-count returns the number of elements, min returns the smallest int, max returns the largest int, sum returns the sum of all the ints and average returns an OptionalDouble (package java.util) containing the average of the ints as a value of type double.

Accepted Answer

IntStream provides terminal operations for common stream reductions, including count, min, max, sum, and average. These operations reduce the stream to a single value by applying a specified function to the elements.

Question 4

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

The correct method to define your own reductions for an IntStream is the `reduce` method. The first argument is indeed an initial value for the reduction, and the second argument is an implementation of the IntBinaryOperator functional interface, which specifies how two given integers are reduced to a single value.

Question 5

Which of the following statements is false?

Accepted Answer

All of the statements are true.

Question 6

Which of the following statements is false?

Accepted Answer

When a terminal operation is called on a Stream, all the intermediate operations are executed for each element of the Stream, and the result of the final operation is returned. Therefore, statement D is false.

Question 7

The basic generic functional interface ________ in package java.util.function contains method test that takes a T argument and returns a boolean. Tests whether the T argument satisfies a condition.

Accepted Answer

The Predicate<T> functional interface has a method called test that takes a T argument and returns a boolean value indicating whether the argument satisfies a certain condition. This makes it the best choice for a functional interface that checks whether a given value satisfies a certain condition.

Question 8

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

Accepted Answer

The terminal operation forEach performs a task on each stream element. This is the appropriate method for performing an operation on all elements of an IntStream. The other options, such as for, forElement or None of the above, are not valid methods for performing actions on IntStream elements.

Question 9

An________ (package java.util.stream) is a stream that manipulates int values.

Accepted Answer

The correct name of the stream that manipulates int values is IntStream. It belongs to the java.util.stream package. Choice A (StreamOfInt) and Choice C (IntegerStream) are not valid names for this stream. Choice B (IStream) is not a standard naming convention for Java streams.

Question 10

IntStream method ________ performs the count, min, max, sum and average operations in one pass of an IntStream's elements and returns the results as an IntSummaryStatistics object (package java.util).

Accepted Answer

The method that performs the count, min, max, sum and average operations in one pass of an IntStream's elements and returns the results as an IntSummaryStatistics object is summaryStatistics. Therefore, the correct choice is D.

Question 11

Which of the following statements is false?

Accepted Answer

All the statements provided are true. A) correctly describes external iteration, where the programmer controls the iteration details. B) is a general truth about programming, where modifying variables can introduce errors. C) accurately describes internal iteration, where the library controls the iteration process.

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

The basic generic functional interface in package java.util.function that contains method get that takes no arguments and produces a value of type T is the Supplier interface. This interface is often used to create a collection object in which stream operation's results are placed, as it can generate and return new instances of a class. Option A, Consumer, is used to accept an argument of type T and perform some operations on it. Option B, Function, is used to transform an argument of type T to a result of type R. Option D, BinaryOperator, is used to operate on two arguments of type T and produce a result of type T.

Question 13

The basic generic functional interface ________ in package java.util.function contains method apply that takes two T arguments, performs an operation on them (such as a calculation) and returns a value of type T.

Accepted Answer

The BinaryOperator<T> functional interface contains a method called apply, which takes two arguments of type T, performs a binary operation on them, and returns a result of type T. This fits the description given in the question. The other options do not fit the description of taking two arguments of type T and returning a result of type T.

Question 14

________ 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

The operation being described is mapping, which transforms the elements of a stream to new values and produces a new stream with the transformed values. Transforming and converting are similar concepts, but do not specifically apply to streams in the context of this question. Translating may also involve changing the type or format of data, but does not necessarily apply to streams or the concept of intermediate operations.

Question 15

The basic generic functional interface ________ in package java.util.function contains method apply that takes a T argument and returns a value of type R. Calls a method on the T argument and returns that method's result.

Accepted Answer

The Function<T,R> interface is the best choice because it contains a method apply, which takes a T argument and returns a value of type R. Additionally, the method applies a transformation on the input argument and returns the result of that transformation. The other interfaces listed do not perform any transformation on the input argument.

Question 16

The basic generic functional interface ________ in package java.util.function contains method accept that takes a T argument and returns void. Performs a task with its T argument, such as outputting the object, invoking a method of the object, etc.

Accepted Answer

The Consumer<T> functional interface contains a method accept(T t) that takes a T argument and returns void. It is used when you want to perform some operation on the object passed to it, such as printing out the object or updating an attribute of the object. This is the most appropriate choice given the requirements listed in the question.

Question 17

Method reduce's first argument is formally called a(n) ________ value-a value that, when combined with any stream element using the IntBinaryOperator produces that element's original value.

Accepted Answer

The formal name of the first argument in the reduce method is the identity value, which is the starting value in the reduction operation and produces the element's original value when combined using the IntBinaryOperator.

Question 18

Which of the following statements is false?

Accepted Answer

All the statements A, B, and C are true regarding the filter operation in Java Streams.

Question 19

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

Accepted Answer

Java SE 8 added functional programming to its existing support for procedural and object-oriented programming paradigms. It also introduced lambda expressions and streams API, which are key features of functional programming.

Question 20

Which of the following statements is false?

Accepted Answer

Method range produces a sequence of values from its first argument up to, but not including, its second argument.

Quiz 17: Lambdas and Streams

Which of the following statements is false?

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

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?

Which of the following statements is false?

The basic generic functional interface ________ in package java.util.function contains method test that takes a T argument and returns a boolean. Tests whether the T argument satisfies a condition.

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

An________ (package java.util.stream) is a stream that manipulates int values.

IntStream method ________ performs the count, min, max, sum and average operations in one pass of an IntStream's elements and returns the results as an IntSummaryStatistics object (package java.util) .

Which of the following statements is false?

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.

The basic generic functional interface ________ in package java.util.function contains method apply that takes two T arguments, performs an operation on them (such as a calculation) and returns a value of type T.

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

The basic generic functional interface ________ in package java.util.function contains method apply that takes a T argument and returns a value of type R. Calls a method on the T argument and returns that method's result.

The basic generic functional interface ________ in package java.util.function contains method accept that takes a T argument and returns void. Performs a task with its T argument, such as outputting the object, invoking a method of the object, etc.

Method reduce's first argument is formally called a(n) ________ value-a value that, when combined with any stream element using the IntBinaryOperator produces that element's original value.

Which of the following statements is false?

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

Which of the following statements is false?