code: private String computeChecksum(File file) {
          try {
              ChecksumUtil cksumUtil =
                  new ChecksumUtil(ChecksumUtil.Algorithm.MD5);
              return cksumUtil.generateChecksum(file);
          } catch (FileNotFoundException e) {
              throw new RuntimeException("File not found: " +
                                         file.getAbsolutePath(), e);
          } catch (IOException e) {
              throw new RuntimeException(e);
          }
      }
docs: /*
  Computes the checksum of a local file