Java Lambda Expressions and Streams

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Question 1

Which of the following is true about lambda expressions in Java?

  • Lambda expressions can be used to define a method.

  • Lambda expressions are instances of functional interfaces.

  • Lambda expressions cannot access instance variables.

  • Lambda expressions are not supported in Java 8.



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Question 2

What is the correct syntax for a lambda expression in Java?



  • (parameter) -> {body}

  • parameter => body

  • parameter -> {body}

  • {parameter} -> body

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Question 3

What will the following lambda expression do? x -> x * 2

  • Doubles the value of x

  • Prints the value of x

  • Doubles the value of x and prints it

  • Nothing

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Question 4

What does the following code snippet represent? () -> { return 42; }

  • A method reference

  • A functional interface

  • A lambda expression

  • An anonymous class

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Question 5

Which of the following functional interfaces can be used with lambda expressions in Java?

  • Runnable

  • Callable

  • Comparator

  • All of the above

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Question 6

Which of the following lambda expressions is correct for a function that takes two integers and returns their sum?

  • (a, b) -> a + b

  • a, b -> {return a + b;}

  • (a, b) { return a + b }

  • (a, b) -> a * b

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Question 7

Which of these statements correctly describes the Stream API in Java 8?

  • Streams are used to process collections of objects sequentially or in parallel.

  • Streams allow modifying the original data source.

  • Streams are primarily used to create new collections.

  • Streams only allow sequential processing.

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Question 8

Which of the following is an intermediate operation in the Stream API?

  • collect()

  • map()

  • forEach()

  • reduce()

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Question 9

Which of the following is a terminal operation in the Stream API?

  • map()

  • filter()

  • reduce()

  • flatMap()

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Question 10

How can a stream be parallelized in Java?

  • By using stream.parallel()

  • By using stream.parallelize()

  • By using parallelStream()

  • By using stream.split()

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