private static String getMd5(ByteBuffer input) {
        MessageDigest md5 = getMd5Instance();
        md5.update(input);
        return HexDump.toHexString(md5.digest()).toLowerCase();
    }
Utilities for mangling config text, finding checksums, finding name and namespace in .def files etc.
config/src/main/java/com/yahoo/vespa/config/util/ConfigUtils.java