public Map<Long, Integer> readLongIntMap(DataInput in) throws IOException {
        return (Map<Long, Integer>) readObject(in);
    }
Reads a Map of Long key and Integer value pairs. This method will return
<tt>null</tt> if the Map written to the stream was <tt>null</tt>.

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