FieldReflectorKey(Class cl,
    ObjectStreamField[] fields,
    ReferenceQueue queue) 
{
            super(cl, queue);
            nullClass = (cl == null);
            StringBuilder sbuf = new StringBuilder();
            for (int i = 0; i <  fields.length; i++) {
                ObjectStreamField f = fields[i];
                sbuf.append(f.getName()).append(f.getSignature());
            }
            sigs = sbuf.toString();
            hash = System.identityHashCode(cl) + sigs.hashCode();
}

 public boolean equals(Object obj) 
{
            if (obj == this) {
                return true;
            }
            if (obj instanceof FieldReflectorKey) {
                FieldReflectorKey other = (FieldReflectorKey) obj;
                Class< ? > referent;
                return (nullClass ? other.nullClass
                                  : ((referent = get()) != null) &&
                                    (referent == other.get())) &&
                    sigs.equals(other.sigs);
            } else {
                return false;
            }
}

 public int hashCode() 
{
            return hash;
}