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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 System.out::println expression?

A - System.out::println method is a static method reference to println method of out object of System class.

B - System.out::println method is a instance method reference to println method of out object of System class.

C - Both of the above.

D - None of the above.

Answer : A

Explanation

System.out::println method is a static method reference to println method of out object of System class.

Q 2 - Which of the following functional interface represents a function that accepts a double-valued argument and produces a result?

A - DoubleFunction<R>

B - DoublePredicate

C - DoubleSupplier

D - DoubleToIntFunction

Answer : A

Explanation

DoubleFunction<R> functional interface represents a function that accepts a double-valued argument and produces a result.

Q 3 - Which of the following functional interface represents an operation upon two int-valued operands and produces an int-valued result?

A - DoubleToLongFunction

B - DoubleUnaryOperator

C - Function<T,R>

D - IntBinaryOperator

Answer : D

Explanation

FunctionIntBinaryOperator functional interface represents an operation upon two int-valued operands and produces an int-valued result.

Q 4 - Which of the following functional interface represents a predicate (Boolean-valued function) of one long-valued argument?

A - LongConsumer

B - LongFunction<R>

C - LongPredicate

D - LongSupplier

Answer : C

Explanation

LongPredicate functional interface represents a predicate (Boolean-valued function) of one long-valued argument.

Q 5 - Which of the following functional interface represents a supplier of results?

A - ObjIntConsumer<T>

B - ObjLongConsumer<T>

C - Predicate<T>

D - Supplier<T>

Answer : D

Explanation

Supplier<T> functional interface represents a supplier of results.

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 - Can you execute javascript code from java 8 code base?

Answer : A

Explanation

Yes! Using ScriptEngineManager, JavaScript code can be called and interpreted in Java.

Q 8 - Using lambda expression, you can refer to final variable or effectively final variable (which is assigned only once).

Answer : B

Explanation

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

Q 9 - Functional interfaces have a single functionality to exhibit.

Answer : B

Explanation

Functional interfaces have a single functionality to exhibit.

Q 10 - Optional.ofNullable method allows passed parameter to be null.

Answer : A

Explanation

Optional.ofNullable method allows passed parameter to be null.

java8_questions_answers.htm

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