Question 1

The type of a lambda is the type of the ________ that the lambda implements.
A) anonymous class
B) functional interface
C) stream
D) collection

Accepted Answer

A lambda expression can only be used to implement a functional interface, since a functional interface has exactly one abstract method and can therefore be implemented with a lambda expression. Other choices such as streams and collections are not related to the type of a lambda.

Question 2

The intermediate Stream operation ________ results in a stream containing only the unique elements.
A) distinct
B) map
C) filter
D) limit

Accepted Answer

The `distinct` operation filters out duplicates from the stream and returns a stream with only unique elements. The other operations (map, filter, limit) either transform elements in the stream or reduce the size of the stream, but do not necessarily remove duplicates.

Question 3

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. A) Consumer B) Function C) Supplier D) Predicate

Accepted Answer

The functional interface that contains a method test that takes a T argument and returns a boolean is the Predicate interface. Therefore, the best choice is D. The Consumer interface contains a method accept that takes a T argument but does not return a value. The Function interface contains a method apply that takes a T argument and returns a result of type R. The Supplier interface contains a method get that takes no arguments and returns a value of type T.

Question 4

Prior to Java SE 8, Java supported three programming paradigms. Java SE 8 adds ________.
A) procedural programming
B) object-oriented programming
C) generic programming
D) functional programming.

Accepted Answer

Prior to Java SE 8, Java supported procedural programming and object-oriented programming. Generic programming was added in Java SE 5. However, Java SE 8 added support for functional programming with the introduction of lambda expressions, streams, and functional interfaces.

Question 5

Which of the following statements is false?
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)

Accepted Answer

Lambda expressions in Java do not have a "default type." The types of parameters in a lambda expression are inferred from the context in which the lambda is used, typically the target functional interface type.

Question 6

Which of the following statements is false?
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.

Accepted Answer

The answer of Which of the following statements is false?
A)...

Question 7

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

Accepted Answer

The Function<T,R> interface is the only generic functional interface that contains a method named apply with the specified behavior of taking a T argument and returning a value of type R. The other interfaces have different methods and behaviors.

Question 8

Which of the following statements is false?
A) Prior to functional programming, you typically determined what you wanted to accomplish, then specified the precise steps to accomplish that task.
B) Using a loop to iterate over a collection of elements is known as external iteration and requires accessing the elements sequentially. Such iteration also requires mutable variables. External iteration is easier to parallelize.
C) Letting the library determine how to iterate over a collection of elements is known as internal iteration.
D) Functional programming focuses on immutability-not modifying the data source being processed or any other program state.

Accepted Answer

The statement regarding external iteration being easier to parallelize is false. In fact, internal iteration is easier to parallelize because the library can handle the parallelism by breaking down the iteration into smaller chunks and distributing them across multiple cores or processors.

Question 9

The basic generic functional interface ________ in package java.util.function contains method get that takes no arguments and returns a value of type T. A) UnaryOperator B) Function C) Supplier D) BinaryOperator

Accepted Answer

The answer of The basic generic functional interface ________ in...

Question 10

Intermediate Stream operation ________ results in a stream with the specified number of elements from the beginning of the original stream.
A) distinct
B) map
C) filter
D) limit

Accepted Answer

The limit operation will return a stream with the specified number of elements from the beginning of the original stream. This is useful when you only need a certain number of elements from a large stream, as it allows you to avoid processing unnecessary elements.

Question 11

Intermediate Stream operation ________ results in a stream in which each element of the original stream is mapped to a new value (possibly of a different type)-e.g., mapping numeric values to the squares of the numeric values. The new stream has the same number of elements as the original stream.
A) mapped
B) map
C) mapper
D) mapping

Accepted Answer

The intermediate stream operation for mapping elements to a new value is called "map".

Question 12

Intermediate operations are________; they aren't performed until a terminal operation is invoked. This allows library developers to optimize stream-processing performance.
A) eager
B) idle
C) lazy
D) inactive

Accepted Answer

Intermediate operations in streams are lazy, meaning they are not executed until a terminal operation is called. This allows for more optimized stream processing as the operations can be combined and executed in a single pass over the data.

Question 13

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

Accepted Answer

The basic generic functional interface that contains a method get that takes no arguments and produces a value of type T is the Supplier interface. This is often used to create a collection object in which a stream operation's results are placed. Therefore, C) Supplier is the best choice.

Question 14

The intermediate Stream operation ________ results in a stream containing only the elements that satisfy a condition.
A) distinct
B) map
C) filter
D) limit

Accepted Answer

The filter operation applies a predicate to each element in the stream and returns a new stream containing only the elements that satisfy the predicate. Therefore, it is the best choice to get a stream of only the elements that meet a certain condition.

Question 15

What is the meaning of ( ) in the following lambda?
() -> System.out.println("Welcome to lambdas!")
A) the lambdas parameters are inferred
B) the lambdas parameters are supplied by a method reference
C) the lambda has an empty parameter list
D) the given expression is not a valid lambda

Accepted Answer

The empty parentheses signify an empty parameter list in the lambda expression.

Question 16

A lambda expression represents a(n) ________ method-a shorthand notation for implementing a functional interface.
A) functional
B) unnamed
C) undesignated
D) anonymous

Accepted Answer

A lambda expression is an anonymous method, meaning it has no name or specific designation. It is used as a shorthand notation for implementing a functional interface, which requires a single abstract method to be implemented. Therefore, option D, anonymous, is the correct choice.

Question 17

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

Accepted Answer

The Consumer<T> interface contains a method accept that takes a T argument and returns void. This interface is meant to perform a task with its T argument, such as outputting the object or invoking a method of the object.

Question 18

2.3 Q3:Terminal operations are eager; they perform the requested operation when they are called.
A) immediate
B) idle
C) lazy
D) eager

Accepted Answer

Terminal operations in programming are eager because they execute the operation immediately when called.

Question 19

The new language and library capabilities that support functional programming were added to Java as part of Project ________.
A) Utilitarian
B) Upsilon
C) Lambda
D) Utility

Accepted Answer

The new language and library capabilities that support functional programming were added to Java as part of Project Lambda.

Question 20

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

Accepted Answer

The BinaryOperator functional interface takes two arguments of type T and returns a value of type T after performing the operation on them. This is the appropriate interface for the described situation. A Consumer interface takes one argument and performs an operation on it, a Function interface takes one argument and returns a value of a possibly different type, and a Supplier interface takes no argument and returns a value.

Quiz 17: Lambdas

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 unique elements.

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.

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

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 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.

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.

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

Intermediate Stream operation ________ results in a stream in which each element of the original stream is mapped to a new value (possibly of a different type) -e.g., mapping numeric values to the squares of the numeric values. The new stream has the same number of elements as the original stream.

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

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

What is the meaning of ( ) in the following lambda? () -> System.out.println("Welcome to lambdas!")

A lambda expression represents a(n) ________ method-a shorthand notation for implementing a functional interface.

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.

2.3 Q3:Terminal operations are eager; they perform the requested operation when they are called.

The new language and library capabilities that support functional programming were added to Java as part of Project ________.

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.