Q.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
Ans : Both the options
Q.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
Ans : Code as data
Q.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
Ans : Runnable r
Q.4 The following are valid lambda expressions, except _________.
A. () -> {return “Mario”;}
B. () -> “Raoul”
C. () -> {}
D. None of the options
Ans : None of the options
Q.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
Ans : WelcomeJava
Q.6 The following lambda expression is valid.
(x, y) -> return x + y
A. True
B. False
Ans : True
Q.7 Parameter types can be inferred in Lambda expressions.
A. True
B. False
Ans : True
Q.8 Which of the following is a valid use of lambda expressions?
A. public void execute(Runnable r){ r.run(); } Execute(() -> {});
B. Predicate
C. public Callable
D. All the options
Ans : public void execute(Runnable r){ r.run(); } Execute(() -> {});
Q.9 Lambda expressions are based on __________
A. Procedural Programming
B. Data Programming
C. Functional Programming
D. All the options
Ans : Functional Programming
Q.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>
Ans : ObjIntConsumer<T>
Q.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); }
Ans : public interface Cards{ int totalCount(int a, int b); }
Q.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
Ans : LongBinaryOperator
Q.13 Which functional interface would you use for the following: No parameters, returns a value.
A. Consumer
B. BiConsumer
C. BiSupplier
D. Supplier
Ans : Supplier
Q.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
Ans : All the options
Q.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>
Ans : Consumer<T>
Q.16 A FunctionalInterface annotation (@FunctionalInterface) is necessary for making an interface a functional interface.
A. True
B. False
Ans : False
Q.17 The following code includes a valid Functional Interface.
package functionalInterfaceExample;
public interface MyFirstFunctionalInterface {
public void firstWork();
@Override
public String toString();
@Override
public boolean equals(Object obj);
}
A. True
B. False
Ans : True
Q.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
Ans : IntToLongFunction
Q.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
Ans : LongBinaryOperator
Q.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
Ans : java.util.stream
Q.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
Ans : Both the options
Q.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
Ans : All the options
Q.23 Each pipeline ends with a/an ____________.
A. Intermediate operation
B. Terminal operation
C. Short circuit operation
D. Any of the options
Ans : Terminal operation
Q.24 Which of these does Stream filter() operates on?
A. Methods
B. Predicate
C. Interface
D. Class
Ans : Predicate
Q.25 Stream operation iterations are internal over the source of elements.
A. True
B. False
Ans : False
