Question#1 Which of the following is correct about Java 8 lambda expression?
a) Optional parenthesis around parameter – There is no need to declare a single parameter in parenthesis. For multiple parameters, parentheses are required.
b) Optional type declaration – There is no need to declare the type of a parameter. The compiler can infer the same from the value of the parameter.
c) Both the options
d) None of the options
Correct Answer is - Both the options
Question#2 Lambda expressions in Java allow us to treat ___________.
a) Data as code
b) Code as data
c) Both the options
d) None of the options
Correct Answer is - Code as data
Question#3 Object o = () -> {System.out.println(“Example”); };
Object o can be replaced with?
a) Function f
b) Runnable r
c) Consumer c
d) All the options
Correct Answer is - Runnable r
Question#4 The following are valid lambda expressions, except _________.
a) () -> {return “Mario”;}
b) () -> “Raoul”
c) () -> {}
d) None of the options
Correct Answer is - None of the options
Question#5 public class Main{
public static void main(String [] args){
String name=”WelcomeJava”;
Runnable r1=() -> System.out.println(name);
String name1 = name.toUpperCase();
Runnable r2=() -> System.out.println(name1);
r1.run();
}
}
What is the output of the above program?
a) WELCOMEJAVA
b) WelcomeJava
c) Runtime error
d) Compilation error
Correct Answer is - WelcomeJava
Question#6 The following lambda expression is valid.
(x, y) -> return x + y
a) True
b) False
Correct Answer is - True
Question#7 Parameter types can be inferred in Lambda expressions.
a) True
b) False
Correct Answer is - True
Question#8 Which of the following is a valid use of lambda expressions?
a) public void execute(Runnable r){ r.run(); } Execute(() -> {});
b) Predicate p = (Apple a) -> a.getWeight(); public interface Predicate { boolean predicate(T t); }
c) public Callable fetch() { Return ? “Tricky example ;-)”; }
d) All the options
Correct Answer is - public void execute(Runnable r){ r.run(); } Execute(() -> {});
Question#9 Lambda expressions are based on __________
a) Procedural Programming
b) Data Programming
c) Functional Programming
d) All the options
Correct Answer is - Functional Programming
Question#10 Which of the following functional interfaces represents an operation that accepts an object-valued and an int-valued argument, and returns no result?
a) Predicate<T>
b) ObjIntConsumer<T>
c) ObjLongConsumer<T>
d) Supplier<T>
Correct Answer is - ObjIntConsumer<T>
Question#11 Which of the following interfaces is a functional interface?
a) public interface NewCards extends Cards{ int totalCount(double a, double b); }
b) public interface InvalidCard{ }
c) public interface Cards{ int totalCount(int a, int b); }
Correct Answer is - public interface Cards{ int totalCount(int a, int b); }
Question#12 Which of the following functional interfaces represents an operation upon two long-valued operands and produces a long-valued result?
a) IntUnaryOperator
b) IntToDoubleFunction
c) LongBinaryOperator
d) LongToLongFunction
Correct Answer is - LongBinaryOperator
Question#13 Which functional interface would you use for the following: No parameters, returns a value.
a) Consumer
b) BiConsumer
c) BiSupplier
d) Supplier
Correct Answer is - Supplier
Question#14 A functional interface acts as a target type for which of the following?
a) Method reference
b) Constructor reference
c) Lambda expression
d) All the options
Correct Answer is - All the options
Question#15 Which of the following functional interfaces represents an operation that accepts a single input argument and returns no result?
a) BooleanSupplier
b) DoubleBinaryOperator
c) DoubleConsumer
d) Consumer<T>
Correct Answer is - Consumer<T>
Question#16 A FunctionalInterface annotation (@FunctionalInterface) is necessary for making an interface a functional interface.
a) True
b) False
Correct Answer is - False
Question#17 The following code includes a valid Functional Interface.
package functionalInterfaceExample;@FunctionalInterface
public interface MyFirstFunctionalInterface {
public void firstWork();
@Override
public String toString();
@Override
public boolean equals(Object obj);
}
a) True
b) False
Correct Answer is - True
Question#18 Which of the following functional interfaces represents a function that accepts an int-valued argument and produces a long-valued result?
a) IntToLongFunction
b) LongBinaryOperator
c) IntLongOperator
d) IntToDoubleFunction
Correct Answer is - IntToLongFunction
Question#19 Which of the following functional interfaces represents an operation upon two long-valued operands and produces a long-valued result?
a) LongToLongFunction
b) IntToDoubleFunction
c) IntUnaryOperator
d) LongBinaryOperator
Correct Answer is - LongBinaryOperator
Question#20 The newly introduced Streams API is available in which package of Java 8?
a) java.io.streams
b) java.util.streams
c) java.util.stream
d) java.io.stream
Correct Answer is - java.util.stream
Question#21 Which of the following is a valid Stream operation type?
a) Intermediate operation
b) Terminal operation
c) Both the options
d) None of the options
Correct Answer is - Both the options
Question#22 Stream operations in Java 8 can be divided into __________.
a) Intermediate types
b) Terminal types
c) None of the options
d) All the options
Correct Answer is - All the options
Question#23 Each pipeline ends with a/an ____________.
a) Intermediate operation
b) Terminal operation
c) Short circuit operation
d) Any of the options
Correct Answer is - Terminal operation
Question#24 Which of these does Stream filter() operates on?
a) Methods
b) Predicate
c) Interface
d) Class
Correct Answer is - Predicate
Question#25 Stream operation iterations are internal over the source of elements.
a) True
b) False
Correct Answer is - False
More Questions on Java8
Question#1 If you wanted to process a stream of names, extract the male names, and store them in a new list, what is the appropriate operation to be used?
a) Both Stream.reduce and Stream.collect
b) Stream.collect
c) Stream.reduce
d) Stream.filter
Answer:-Stream.collect
Question#2 Repeating annotations can be added with which of the following declarations?.
a) Declare just the repeatable annotation type
b) 1. Declare a repeatable annotation type
2. Declare the modifier annotation type
c) 1. Declare a repeatable annotation type
2. Declare the containing annotation type
d) None of the options
Answer:-1. Declare a repeatable annotation type
2. Declare the containing annotation type
Question#3 The terminal operation produces another stream as its output.
a) True
b) False
Answer:-False
Question#4 Optional type validation can be used to substitute runtime validations.
a) True
b) False
Answer:-False
Question#5 Repeating annotations can be retrieved using _________
a) getAnnotationsList()
b) getAnnotations()
c) getAnnotationsByType()
d) getAnnotationsByValue()
Answer:-getAnnotationsByType()
Question#6 On which of these can annotations be used on in Java 8?
a) Local variables
b) Super classes
c) Generic types
d) All the options
Answer:-All the options
Question#7 Type annotation is used to depict the non-blank string value _________
a) @NotBlank
b) @NotEmpty
c) @NonBlank
d) None of the options
Answer:-@NotBlank
Question#8 LocalDate date1 = LocalDate.now();
LocalDate date2 = date1.plus(1, ChronoUnit.MONTHS);
Period period = Period.between(date2, date1);
System.out.println(“Period: ” + period);
Choose the correct output.
a) Compilation error
b) Period: P-1M
c) Period: 1
d) Runtime error
Answer:-Period: P-1M
Question#9 Which method is used to connect the consumer to the source in reactive programming?
a) connectTo()
b) subscribe()
c) subscribeTo()
d) connect()
Answer:-subscribe()
Question#10 The method used to fetch the parameter types using method parameter reflection is _________.
a) getParameterizedTypes()
b) getTypeParam()
c) getParamType()
d) getParameterizedType()
Answer:-getParameterizedType()
Question#11 Which of these should be used to show package-level and class-level dependencies of Class files in Java 8?
a) dep
b) jdeps
c) ideps
d) jdep
Answer:-jdeps
Question#12 Which of the following methods preserve parameter names in Java bytecode (through reflection API)?
a) All public methods
b) All methods
c) specify -parameters during compilation
d) specify -params during compilation
Answer:-All public methods
Question#13 Reactive Programming deals with ____________.
a) Synchronous data
b) Asynchronous data
c) Both the options
d) None of the options
Answer:-Asynchronous data
Question#14 Identify the intermediate and terminal operations in the code.
double average = roster
.stream()
.filter(p -> p.getGender() == Person.Sex.MALE)
.mapToInt(Person::getAge)
.average()
.getAsDouble();
a) Intermediate: filter, mapToInt Terminal: average
b) Intermediate: filter Terminal: mapToInt, average
c) Intermediate:average Terminal: filter, mapToInt
d) Intermediate: filter, mapToInt Terminal: getAsDouble
Answer:-Intermediate: filter, mapToInt Terminal: average
