16. Which of these types cannot be used to initiate a generic type?

1. 1. Collections

   
   
   

   2. Primitive Types

   
   
   

   3. Integer class

   
   
   

   4. Float class

   
   
   

   5. None of these

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   Primitive Types

---

17. Which of these instance cannot be created?

1. 1. Generic type instance

   
   
   

   2. Collection instances

   
   
   

   3. Generic class instance

   
   
   

   4. Integer instance

   
   
   

   5. None of these

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   It is not possible to create generic type instances. Example – “P obj = new P()” will give a compilation error.

---

---

18. Which of these data type cannot be type parameterized?

1. 1. Set

   
   
   

   2. Map

   
   
   

   3. List

   
   
   

   4. Array

   
   
   

   5. None of these

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   Array

---

19. What is the output of this program?
    

    import java.util.*;
       public class Result
        {
            public static double sumOfList(List list) 
            {
                double var = 0.0;
                for (Number num : list)
                    var += num.doubleValue();
                return var;
            }
            public static void main(String args[])
            {
               List obj = Arrays.asList(4.3, 5.6, 7.8);
               System.out.println(sumOfList(obj));
            }
        }
    

1. 1. 17.7

   
   
   

   2. 4.3

   
   
   

   3. 5.6

   
   
   

   4. 7.8

   
   
   

   5. None of these

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   17.7

---

---

20. Which of these is wildcard symbol?

1. 1. &

   
   
   

   2. %

   
   
   

   3. ?

   
   
   

   4. !

   
   
   

   5. None of these

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   In generic code, the question mark (?), called the wildcard, represents an unknown type.

---