Java Collections Test – 1

1. What will be the output of the following Java program?

 
    import java.util.*;
    class Collection_iterators 
    {
        public static void main(String args[]) 
        {
            LinkedList list = new LinkedList();
            list.add(new Integer(2));
            list.add(new Integer(8));
            list.add(new Integer(5));
            list.add(new Integer(1));
            Iterator i = list.iterator();
            Collections.reverse(list);
	    while(i.hasNext())
	        System.out.print(i.next() + " ");
        }
    }

2. Which of these iterators can be used only with List?

3. Which of these return type of hasNext() method of an iterator?

4. Which of these exceptions is thrown by remover() method?

5. Which of these is a method of ListIterator used to obtain index of previous element?

6. Which of these methods is used to obtain an iterator to the start of collection?

7. Which of these methods can be used to move to next element in a collection?

8. What will be the output of the following Java program?

 
    import java.util.*;
    class Collection_iterators 
    {
        public static void main(String args[]) 
        {
            ListIterator a = list.listIterator();
                if(a.previousIndex()! = -1)
                    while(a.hasNext())
	                System.out.print(a.next() + " ");
                else
                   System.out.print("EMPTY");
        }
    }

9. What will be the output of the following Java program?

 
    import java.util.*;
    class Collection_iterators 
    {
        public static void main(String args[]) 
        {
            LinkedList list = new LinkedList();
            list.add(new Integer(2));
            list.add(new Integer(8));
            list.add(new Integer(5));
            list.add(new Integer(1));
            Iterator i = list.iterator();
            Collections.reverse(list);
	    Collections.shuffle(list);
            i.next();
            i.remove();
            while(i.hasNext())
	        System.out.print(i.next() + " ");
        }
    }

10. What will be the output of the following Java program?

 
    import java.util.*;
    class Collection_iterators 
    {
        public static void main(String args[]) 
        {
            LinkedList list = new LinkedList();
            list.add(new Integer(2));
            list.add(new Integer(8));
            list.add(new Integer(5));
            list.add(new Integer(1));
            Iterator i = list.iterator();
            Collections.reverse(list);
	    Collections.sort(list);
            while(i.hasNext())
	        System.out.print(i.next() + " ");
        }
    }