How to cast generic List types in java?

Well, I have a class Customer (no base class).

I need to cast from LinkedList to List. Is there any clean way to do this?

Just so you know, I need to cast it to List. No other type will do. (I'm developing a test fixture using Slim and FitNesse).

EDIT: Okay, I think I need to give code examples here.

import java.util.*;
public class CustomerCollection
{
    protected LinkedList<Customer> theList;

    public CustomerCollection()
    {
        theList = new LinkedList<Customer>();
    }

    public void addCustomer(Customer c){ theList.add(c); }
    public List<Object> getList()
    {
        return (List<? extends Object>) theList;
    }
}

So in accordance with Yuval A's remarks, I've finally written the code this way. But I get this error:

CustomerCollection.java:31: incompatible types
found   : java.util.List<capture#824 of ? extends java.lang.Object>
required: java.util.List<java.lang.Object>
        return (List<? extends Object>)theList;
               ^
1 error

So, what's the correct way to do this cast?