Note that serialization of bloom filters requires the proper serialization of funnels. When possible, it is recommended that funnels be implemented as a single-element enum to maintain serialization guarantees. See Effective Java (2nd Edition), Item 3: "Enforce the singleton property with a private constructor or an enum type". For example:

   public enum PersonFunnel implements Funnel<Person> {
     INSTANCE;
     public void funnel(Person person, PrimitiveSink into) {
       into.putUnencodedChars(person.getFirstName())
           .putUnencodedChars(person.getLastName())
           .putInt(person.getAge());
     }
   }