code: protected int readUByte(InputStream in) throws IOException { // IA VISIBILITY CHANGE FOR SUBCLASS USE
          int b = in.read();
          if (b == -1) {
              throw new EOFException();
          }
          if (b < -1 || b > 255) {
              // Report on this.in, not argument in; see read{Header, Trailer}.
              throw new IOException(this.in.getClass().getName()
                  + ".read() returned value out of range -1..255: " + b);
          }
          return b;
      }
docs: /*
  Reads unsigned byte.