@Override
        public int hashCode() {
            return
                (mObj1 == null ? 0 : mObj1.hashCode()) +
                (mObj2 == null ? 0 : mObj2.hashCode());
        }
Returns an estimate for the maximum length date that this date
formatter will produce. The actual formatted length will almost always
be less than or equal to this amount.
@return an estimate of the maximum length
xmppserver/src/main/java/org/jivesoftware/util/FastDateFormat.java