16. If the size of the array used to implement a circular queue is MAX_SIZE. How rear moves to traverse inorder to insert an element in the queue?

1. 1. rear=rear%(MAX_SIZE+1)

   
   
   

   2. rear=rear+(1%MAX_SIZE)

   
   
   

   3. rear=(rear+1)%MAX_SIZE

   
   
   

   4. rear=(rear%1)+MAX_SIZE

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   The front and rear pointer od circular queue point to the first element.

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17. What is the output of below code snippet?
    

    import java.util.*;
    public class HashSet_Example 
    {
    	public static void main(String[] args) 
            {
    		Set setobj = new HashSet();
    		setobj.add(new Long(20));
    		setobj.add(new Integer(30));
    		for(Object object : setobj)
                    {
    		    System.out.println("test - "+object);
    		}
    	}
    }
    

1. 1. test - 20

   
   
   

   2. test - 30

   
   
   

   3. test - 20
      test - 30

   
   
   

   4. test

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   Integer and Long are two different data types and different objects. So they will be treated as unique elements and not overridden.

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18. Set has contains(Object o) method.

1. 1. False

   
   
   

   2. True

   
   
   

   3. False and True both

   
   
   

   4. All of Above

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   Set has contains(Object o) method instead of get(Object o) method as get is needed for comparing object and getting corresponding value.

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19. What is the difference between TreeSet and SortedSet?

1. 1. TreeSet is an interface; SortedSet is a concrete class

   
   
   

   2. TreeSet is more efficient than SortedSet

   
   
   

   3. SortedSet is an interface; TreeSet is a concrete class

   
   
   

   4. SortedSet is more efficient than TreeSet

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   SortedSet is an interface. It maintains an ordered set of elements. TreeSet is an implementation of SortedSet.

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20. What happens if two threads simultaneously modify TreeSet?

1. 1. IteratorModificationException is thrown

   
   
   

   2. FailFastException is thrown

   
   
   

   3. Both threads can perform action successfully

   
   
   

   4. ConcurrentModificationException is thrown

   
   
   

   5. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   TreeSet provides fail-fast iterator. Hence when concurrently modifying TreeSet it throws ConcurrentModificationException.

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