Clear () method - undefined for type ShoppingCart

I am implementing a JSP shopping site. I have a Java object with a name ShoppingCartand one Item element. There ShoppingCartis a vector containing Item objects. The idea is when I call the method addItem(), I use: -

cart.addItem(name, image, price, details);

ensuring that ShoppingCart is already announced : -

ShoppingCart cart = new ShoppingCart("file_path_to_file"); 

and contents addItem: -

public void addItem(String name, String image, String price, String detail) throws IOException  
{  
     items.add(new Item(name, image, price, detail));  
     this.saveMe();  
}  

where items is a vector. It works great. However, I created a new clear method: -

public void clear() throws IOException  
{  
    items.clear();  
    this.saveMe();  
}  

The saveMe method simply saves the Object file: -

private void saveMe() throws IOException  
{  
     FileOutputStream fos = new FileOutputStream(this.filename);  
     ObjectOutputStream oos = new ObjectOutputStream(fos)  
     oos.writeObject(this.items);  
     oos.close();  
}  

When I call the clear method using: -

cart.clear();

I get an error: -

Error in line: 108 in jsp file: /project/cart.jsp The clear () method is undefined for type ShoppingCart

Can someone help with any ideas I can try to solve this problem?