JSP session bean call error

package businessLayer;

import businessLayer.ItemException;

import java.util.Vector;

import javax.ejb.CreateException;
import javax.ejb.SessionBean;
import javax.ejb.SessionContext;

public class cartBeanBean implements SessionBean  
{
  private SessionContext context;
  Vector contents;

  public void ejbCreate()
  {
     Vector contents = new Vector();
  }
  
  public void ejbActivate()
  {
  }

  public void ejbPassivate()
  {
  }

  public void ejbRemove()
  {
  }

  public void setSessionContext(SessionContext ctx)
  {
    this.context = ctx;
  }
  
  public void addItem(String itemID)
  {
    contents.add(itemID);
  }
  
  public void removeItem(Integer itemID) throws ItemException
  {
    boolean result = contents.remove(itemID);
    if (result == false)
      throw new ItemException("Item with the ID of "+itemID+" is not on the list");
  }
  
  public Vector getContents()
  {
    return contents;
  }
}

<%@ page import="java.util.Vector, javax.naming.*, javax.rmi.*, businessLayer.cartBeanHome, businessLayer.cartBean"%>
<%! 
//declare a "global" reference to an instance of the home interface of the session bean
public void jspInit() { 
  //obtain an instance of the home interface
  try {
    InitialContext ic = new InitialContext();
    Object objRef = ic.lookup("cartBean");
    cartBeanHome home = (cartBeanHome)PortableRemoteObject.narrow(objRef,cartBeanHome.class);
    cartBean cart = home.create();
    int one = 1;
    Integer oneI = new Integer(one);
    cart.addItem(oneI);
  }
  catch (Exception ex){
    System.err.println("Caught an unexpected exception: " + ex.getMessage());
    System.exit(1);
  } 
}
%>