JavaProgrammingWorld.com

QUESTION : 1

   What is the result of attempting to compile and run the following code?

  public class Test1{
     public static void main(String[] args)
     {
     Integer int1 = new Integer(10);
     Vector vec1 = new Vector();
     LinkedList list = new LinkedList();
     vec1.add(int1);
     list.add(int1);
     if(vec1.equals(list)) System.out.println("equal");
     else  System.out.println("not equal");
      }
  } 

1. The code will fail to compile.
2. Runtime error due to incompatible object comparison
3. Will run and  print "equal".
4. Will run and  print "not equal".

ANS : 3

        correct answer/s : 3 

QUESTION : 2

   What is the result of attempting to compile and run the following code?
           public class Test {

              public static void main(String[] args){
               Integer a = new Integer(4);
               Integer b = new Integer(8);
               Integer c = new Integer(4);
               HashSet hs = new HashSet();
               hs.add(a);
               hs.add(b);
               hs.add(c);
               System.out.println(hs);
              }
         }

1. Will print [8, 4]
2. Will print [4, 8, 4]
3. Will print [8, 4, 4]

ANS : 1

        correct answer/s : 1

QUESTION : 3

   What is the result of attempting to compile and run the following code?
           public class Test {

              public static void main(String[] args){
               Integer a = new Integer(4);
               Integer b = new Integer(8);
               Integer c = new Integer(4);
               TreeSet hs = new TreeSet();
               ts.add(a);
               ts.add(b);
               ts.add(c);
               System.out.println(ts);
              }
         }

1. Will print [8, 4]
2. Will print [4, 8, 4]
3. Will print [8, 4, 4]
4. Will print [4, 8]
5. Will print [4, 4, 8]

ANS : 4

       correct answer/s : 4

QUESTION : 4

     What will this print out ?

           public class Test {

              public static void main(String[] args){
               Integer a = new Integer(8);
               Integer b = new Integer(4);
               Integer c = new Integer(4);
               Vector vec = new Vector();
               Iterator itr;
               vec.add(a);
               vec.add(b);
               vec.add(c);
               itr = vec.iterator();
                  while (itr.hasNext()) {
                   System.out.println("" + itr.next());
                  }
              }
         }

1.  8 , 4 and 4
2.  4 , 4 and 8
3.  8 and 4
4.  4 and 8

ANS : 1

       correct answer/s : 1

QUESTION : 5

   Which of these statements are true?

1. HashTable is a sub class of Dictionary
2. ArrayList is a sub class of Vector
3. LinkedList is a subclass of ArrayList
4. Stack is a subclass of Vector

ANS : 1,4

       correct answer/s : 1,4

QUESTION : 6

   Which of these statements are true? 

1. LinkedList extends List
2. AbstractSet extends Set
3. HashSet extends AbstractSet
4. WeakHashMap extends HashMap
5. TreeSet extends AbstractSet

ANS : 3,5

       correct answer/s : 3,5

QUESTION : 7

    Which of these statements are true? 

1. A HashSet does not permit duplicates
2. A Vector permits duplicates
3. A TreeSet is an ordered Set
4. A LinkedList is sorted in descending order
5. A LinkedList is sorted in ascending order 

ANS : 1,2,3

       correct answer/s : 1,2,3

QUESTION : 8

      True or False.
     A WeakHashMap is synchronized.

1. True
2. False

ANS : 2

       correct answer/s : 2

QUESTION : 9

      True or False.
     A Set rejects duplicates and is ordered

1. True
2. False

ANS : 2

       correct answer/s : 2

QUESTION : 10

     Select the true statements

1. AbstractSet extends AbstractCollection
2. AbstractList extends AbstractCollection
3. HashSet extends AbstractSet
4. Vector extends AbstractList
5. AbstrctSequentialList extends AbstractList
6. LinkedList extends AbstrctSequentialList

ANS : 1,2,3,4,5,6

       correct answer/s : 1,2,3,4,5,6