public void writeLongIntMap(DataOutput out, Map<Long, Integer> map) throws IOException {
        writeObject(out, map);
    }
Writes a Map of Long key and Integer value pairs. This method handles
the case when the Map is <tt>null</tt>.

@param out the output stream.
@param map the Map of Long key/Integer value pairs.
@throws IOException if an error occurs.
xmppserver/src/main/java/org/jivesoftware/util/cache/DefaultExternalizableUtil.java