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Advanced Java

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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.

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 a supplier of double-valued results?

A - DoubleFunction<R>

B - DoublePredicate

C - DoubleSupplier

D - DoubleToIntFunction

Answer : C

Explanation

DoubleSupplier functional interface represents a supplier of double-valued results.

Q 3 - Which of the following functional interface represents an operation on a single double-valued operand that produces a double-valued result?

A - DoubleToLongFunction

B - DoubleUnaryOperator

C - Function<T,R>

D - IntBinaryOperator

Answer : B

Explanation

DoubleUnaryOperator functional interface represents an operation on a single double-valued operand that produces a double-valued result.

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

Answer : B

Explanation

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

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

A - ToLongBiFunction<T,U>

B - ToLongFunction<T>

C - UnaryOperator<T>

D - ToIntFunction<T>

Answer : A

Explanation

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

Q 6 - What is the purpose of filter 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 : C

Explanation

The 'filter' method is used to eliminate elements based on a criteria.

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

A - Optional is a container object which is used to contain not-null objects.

B - Optional object is used to represent null with absent value.

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 method of Base64 class returns a Base64.Encoder that encodes using the MIME type base64 encoding scheme?

Answer : D

Explanation

getMimeEncoder() method of Base64 class returns a Base64.Encoder that encodes using the MIME type base64 encoding scheme.

Q 9 - Stream operations do the iterations internally over the source elements provided.

A - false

B - true

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 - In which of the following type of Base64 encoding, Output is mapped to a set of characters lying in A-Za-z0-9+/?

A - Simple

B - URL

C - MIME

D - None of the above.

Answer : A

Explanation

Simple − Output is mapped to a set of characters lying in A-Za-z0-9+/.

java8_questions_answers.htm