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Java 8 Online Quiz

Following quiz provides Multiple Choice Questions (MCQs) related to Java 8. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using Show Answer button. You can use Next Quiz button to check new set of questions in the quiz.

Questions and Answers

Q 1 - Which of the following is correct about Java 8 lambda expression?

A - Using lambda expression, you can refer to final variable or effectively final variable (which is assigned only once).

B - Lambda expression throws a compilation error, if a variable is assigned a value the second time.

C - Both of the above.

D - None of the above.

Answer : C

Explanation

Both of the above options are correct.

Q 2 - Which of the following functional interface represents an operation that accepts a single input argument and returns no result?

A - BooleanSupplier

B - Consumer<T>

C - DoubleBinaryOperator

D - DoubleConsumer

Answer : B

Explanation

Consumer<T> functional interface represents an operation that accepts a single input argument and returns no result.

Q 3 - Which of the following functional interface represents a function that accepts an int-valued argument and produces a double-valued result?

A - IntToDoubleFunction

B - IntToLongFunction

C - IntUnaryOperator

D - LongBinaryOperator

Answer : A

Explanation

IntPredicate functional interface represents a function that accepts an int-valued argument and produces a double-valued result.

Q 4 - Which of the following functional interface represents an operation that accepts a single long-valued argument and returns no result?

A - LongConsumer

B - LongFunction<R>

C - LongPredicate

D - LongSupplier

Answer : A

Explanation

LongConsumer functional interface represents an operation that accepts a single long-valued argument and returns no result.

Q 5 - Which of the following functional interface represents a function that accepts two arguments and produces a double-valued result?

A - ToDoubleBiFunction<T,U>

B - ToDoubleFunction<T>

C - ToIntBiFunction<T,U>

D - ToIntFunction<T>

Answer : A

Explanation

ToDoubleBiFunction<T,U> functional interface represents a function that accepts two arguments and produces a double-valued result.

Q 6 - How will you call a default method of an interface in a class?

A - Using super keyword along with interface name.

B - Using name of the interface.

C - Both of the above.

D - None of the above.

Answer : A

Explanation

Using super keyword along with interface name.

Q 7 - Which of the following API represents a specialized date-time API to deal with various timezones in java8?

C - Both of the above.

D - None of the above.

Answer : B

Explanation

Zoned − Specialized date-time API to deal with various timezones.

Q 8 - Which of the following is the correct lambda expression which add two numbers and return their sum?

A - (int a, int b) -> { return a + b;};

B - (a, b) -> {return a + b;};

C - Both of the above.

D - None of the above.

Answer : C

Explanation

Both of the above options are correct.

Q 9 - Stream takes Collections, Arrays, or I/O resources as input source.

Answer : A

Explanation

Stream takes Collections, Arrays, or I/O resources as input source.

Q 10 - Optional.orElse method returns the value if present otherwise returns the default value passed.

Answer : B

Explanation

Optional.orElse method returns the value if present otherwise returns the default value passed.

java8_questions_answers.htm

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