code: public static String getSHA256Checksum(File file) throws IOException, NoSuchAlgorithmException {
          final byte[] b = getChecksum(SHA256, file);
          return getHex(b);
      }
docs: Calculates the SH256 checksum of a specified file.
  
  @param file the file to generate the MD5 checksum
  @return the hex representation of the SHA1 hash
  @throws java.io.IOException when the file passed in does not exist
  @throws java.security.NoSuchAlgorithmException when the SHA1 algorithm is not available