VEctor: Problem in arithmetical operation

Question

The problem with the following code is that when an element is accessed with v.elementAt() the compilation is OK. But if I try to do some arithmetic operation on the element, it won't compile, giving the message -
VectorDemo.java:36: operator * cannot be applied to java.lang.Object, int
System.out.println("Result: "+v.elementAt(3)*2);
Is it because of <Object> type declaration of Vector? If so how to do arithmetic operation with an element of a vector which may have Double, Float or Integer type of elements in the same vector?
import java.util.*;
class VectorDemo
     public static void main(String args[])
          Vector<Object> v=new Vector<Object>(3,2);
          System.out.println("Initial size: "+v.size());
          System.out.println("Initial capacity: "+v.capacity());
          v.addElement(new Integer(1));
          v.addElement(new Integer(2));
          v.addElement(new Integer(3));
          v.addElement(new Integer(4));
          System.out.println("Capacity after four additions: "+v.capacity());
          v.addElement(new Double(5.45));
          System.out.println("Current capacity : "+v.capacity());
          v.addElement(new Double(6.08));
          v.addElement(new Integer(7));
          System.out.println("Current capacity : "+v.capacity());
          v.addElement(new Float(9.4));
          v.addElement(new Integer(10));
          System.out.println("Current capacity : "+v.capacity());
          v.addElement(new Integer(11));
          v.addElement(new Integer(12));
          System.out.println("First element : "+v.firstElement());
          System.out.println("Last element : "+v.lastElement());
          System.out.println("Find Result: "+v.elementAt(3));     //<------ if replaced with:
                                //System.out.println("Find Result: "+v.elementAt(3)*2);
          if(v.contains(new Integer(3)))
               System.out.println("Vector contains 3.");
          Enumeration vEnum=v.elements();
          System.out.println("\nElements in vector: ");
          while(vEnum.hasMoreElements())
               System.out.println(vEnum.nextElement()+" ");
          System.out.println();
}

Answer 1

Here's the correct code.
import java.util.*;
import java.lang.Number;
class VectorDemo
     public static void main(String args[])
          //initial size is 3, increment is 2
          String s;
          int i=0;
          Vector<Number> v=new Vector<Number>(3,2);
          System.out.println("Initial size: "+v.size());
          System.out.println("Initial capacity: "+v.capacity());
          v.addElement(new Integer(1));
          v.addElement(new Integer(2));
          v.addElement(new Integer(3));
          v.addElement(new Integer(4));
          System.out.println("Capacity after four additions: "+v.capacity());
          v.addElement(new Double(5.45));
          System.out.println("Current capacity : "+v.capacity());
          v.addElement(new Double(6.08));
          v.addElement(new Integer(7));
          System.out.println("Current capacity : "+v.capacity());
          v.addElement(new Float(9.4));
          v.addElement(new Integer(10));
          System.out.println("Current capacity : "+v.capacity());
          v.addElement(new Integer(11));
          v.addElement(new Integer(12));
          System.out.println("First element : "+v.firstElement());
          System.out.println("Last element : "+v.lastElement());
          System.out.println("Result: "+Integer.parseInt(v.elementAt(3).toString())*2);
          if(v.contains(new Integer(3)))
               System.out.println("Vector contains 3.");
          //enumerate the elements in the vector.
          Enumeration vEnum=v.elements();
          System.out.println("\nElements in vector: ");
          while(vEnum.hasMoreElements())
               System.out.println(vEnum.nextElement()+" ");
          System.out.println();
}