public List<String> readStringList(DataInput in) throws IOException {
        return strategy.readStringList(in);
    }
Reads a List of Strings. This method will return {@code null} if the List
written to the stream was {@code null}.

@param in the input stream.
@return a List of Strings.
@throws IOException if an error occurs.
xmppserver/src/main/java/org/jivesoftware/util/cache/ExternalizableUtil.java