Metal Aluminium is present in chocolate wrappers.

Dealing with primitives as objects is easier at times. Most of the objects collection store objects and not primitive types. Many utility methods are provided by wrapper classes. To get these advantages we need to use wrapper classes. As they are objects, they can be stored in any of the collection and pass this collection as parameters to the methods.

Features of the Java wrapper Classes:

- Wrapper classes convert numeric strings into numeric values.

- The way to store primitive data in an object.

- The valueOf() method is available in all wrapper classes except Character

- All wrapper classes have typeValue() method. This method returns the value of the object as its primitive type.

Wrapper classes wrap primitive values in a class and offers utility to access them through objects. Some of the primitive wrapper data types are:

Byte, short, int, long, float, double, char, Boolean.

Example: 

Create a class name VectorAdd to populate it with integer values using the add(int, object) method.

public class VectorAdd

{

       public static void main(String argv[])

       {

             Vector v = new Vector();

             v.add(0,new Integer(10));

             v.add(1,new Integer(20));

             v.add(2,new Integer(30));

             for(int i=0; i < v.size();i ++)

             {

                  Integer iw =(Integer) v.get(i);

                  System.out.println(iw);

             }

       }

}