code: private static String readOID(ByteArrayInputStream bais, int oid_len) throws IOException {
          byte[] oid_tmp_arr = new byte[oid_len];
          bais.read(oid_tmp_arr, 0, oid_len);
          byte[] oid_arr = new byte[oid_len + 2];
          oid_arr[0] = ASN_TAG_OID;
          oid_arr[1] = (byte) oid_len;
          System.arraycopy(oid_tmp_arr, 0, oid_arr, 2, oid_len);
          return decodeOID(oid_arr);
      }
docs: /*
  WARNING: The stream must have read up to the OID length.
  This method reads and decodes the OID after the length.