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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 - Optional curly braces - No need to use curly braces in expression body if the body contains a single statement.

B - Optional return keyword - The compiler automatically returns the value if the body has a single expression to return the value.

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 upon two double-valued operands and producing a double-valued result?

A - BooleanSupplier

B - Consumer<T>

C - DoubleBinaryOperator

D - DoubleConsumer

Answer : C

Explanation

DoubleBinaryOperator functional interface represents an operation upon two double-valued operands and producing a double-valued result.

Q 3 - Which of the following functional interface represents a supplier of int-valued results?

A - IntConsumer

B - IntFunction<R>

C - IntPredicate

D - IntSupplier

Answer : D

Explanation

IntPredicate functional interface represents a supplier of int-valued results.

Q 4 - Which of the following functional interface represents a function that accepts a long-valued argument and produces a double-valued result?

A - LongToDoubleFunction

B - LongToIntFunction

C - LongUnaryOperator

D - ObjDoubleConsumer<T>

Answer : A

Explanation

LongToDoubleFunction functional interface represents a function that accepts a long-valued argument and produces a double-valued result.

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 - What is the purpose of limit method of stream in java 8?

A - Iterate each element of the stream.

B - Map each element to its corresponding result.

C - Eliminate elements based on a criteria

D - Reduce the size of the stream

Answer : D

Explanation

The 'limit' method is used to reduce the size of the stream.

Q 7 - Which of the following is correct about Optional in java8?

A - This class has various utility methods to facilitate code to handle values as 'available' or 'not available' instead of checking null values.

B - It is introduced in Java 8 and is similar to what Optional is in Guava.

C - Both of the above.

D - None of the above.

Answer : C

Explanation

Both of the above options are correct.

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 operations do the iterations internally over the source elements provided.

Answer : B

Explanation

Stream operations do the iterations internally over the source elements provided, in contrast to Collections where explicit iteration is required.

Q 10 - java.util.Date is not thread safe, thus developers have to deal with concurrency issue while using date.

Answer : A

Explanation

java.util.Date is not thread safe, thus developers have to deal with concurrency issue while using date.

java8_questions_answers.htm

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