code: private static byte[] readFrom(File src) throws IOException {
          long srcsize = src.length();
          if (srcsize > Integer.MAX_VALUE) {
              throw new IllegalArgumentException(
                      "File too big to be loaded in memory");
          }
          FileInputStream inputStream = new FileInputStream(src);
          byte[] array = new byte[(int) srcsize];
          try {
              FileChannel fileChannel = inputStream.getChannel();
              ByteBuffer byteBuffer = ByteBuffer.wrap(array);
              int read = 0;
              while (read < srcsize) {
                  read += fileChannel.read(byteBuffer);
              }
          } finally {
              inputStream.close();
          }
          return array;
      }
docs: Utility function
  @return the array of bytes