Java 8 Mock Test

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

Answer : C

Explanation

Both of the above options are correct.

Q 4 - Which of the following is correct about Java 8 lambda expression?

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

A - Lambda expressions are used primarily to define inline implementation of a functional interface.

Answer : C

Explanation

Both of the above options are correct.

Q 5 - Which of the following is correct about Java 8 lambda expression?

B - Lambda expression eliminates the need of anonymous class and gives a very simple yet powerful functional programming capability to Java.

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

Answer : C

Explanation

Both of the above options are correct.

Q 6 - Which of the following is correct about Java 8 lambda expression?

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

A - Method references help to point to methods by their names.

Answer : C

Explanation

Both of the above options are correct.

Q 7 - Which of the following is correct about Java 8 method references?

B - A method reference is described using :: (double colon) symbol.

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

Answer : C

Explanation

Both of the above options are correct.

Q 8 - Which of the following is correct about System.out::println expression?

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

Answer : A

Explanation

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

Q 9 - Which of the following functional interface represents an operation that accepts two input arguments, and returns no result?

Answer : A

Explanation

BiConsumer<T,U> functional interface represents an operation that accepts two input arguments, and returns no result.

Q 10 - Which of the following functional interface represents an operation that accepts two input arguments, and returns a result?

Answer : B

Explanation

BiFunction<T,U> functional interface represents an operation that accepts two input arguments, and returns a result.

Q 11 - Which of the following functional interface represents an operation upon two operands of the same type, producing a result of the same type as the operands?

Answer : C

Explanation

BinaryOperator<T> functional interface represents an operation upon two operands of the same type, producing a result of the same type as the operands.

Q 12 - Which of the following functional interface represents a predicate (Boolean-valued function) of two arguments?

Answer : D

Explanation

BiPredicate<T,U> functional interface represents a predicate (Boolean-valued function) of two arguments.

Q 13 - Which of the following functional interface represents a supplier of Boolean-valued results?

Answer : A

Explanation

BooleanSupplier functional interface represents a supplier of Boolean-valued results.

Q 14 - Which of the following functional interface represents an operation that accepts a single input argument and returns no result?

Answer : B

Explanation

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

Q 15 - Which of the following functional interface represents an operation upon two double-valued operands and producing a double-valued result?

Answer : C

Explanation

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

Q 16 - Which of the following functional interface represents an operation that accepts a single double-valued argument and returns no result?

Answer : D

Explanation

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

Q 17 - Which of the following functional interface represents a function that accepts a double-valued argument and produces a result?

Answer : A

Explanation

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

Q 18 - Which of the following functional interface represents a predicate of one double-valued argument?

Answer : B

Explanation

DoublePredicate functional interface represents a predicate (Boolean-valued function) of one double-valued argument.

Q 19 - Which of the following functional interface represents a supplier of double-valued results?

Answer : C

Explanation

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

Q 20 - Which of the following functional interface represents a function that accepts a double-valued argument and produces an int-valued result?

Answer : D

Explanation

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

Q 21 - Which of the following functional interface represents a function that accepts a double-valued argument and produces a long-valued result?

Answer : A

Explanation

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

Q 22 - Which of the following functional interface represents an operation on a single double-valued operand that produces a double-valued result?

Answer : B

Explanation

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

Q 23 - Which of the following functional interface represents a function that accepts one argument and produces a result?

Answer : C

Explanation

Function<T,R> functional interface represents a function that accepts one argument and produces a result.

Q 24 - Which of the following functional interface represents an operation upon two int-valued operands and produces an int-valued result?