Java APIs

When I use the code:

import java.util.*;

    class BagTest<E> extends LinkedList<E> {
   
   /** Add object to bag 
   * @param ob the object to add
   */  
       public void add(E ob) {
         super.addLast(ob);
      }
   
   }

I get the error:
BagTest.java:8: add(E) in BagTest cannot implement add(E) in java.util.Collection; attempting to use incompatible return type

Now I know that add in Collection is boolean, but I'm either overriding or creating a new method ???