code: private void verifyXopResponse(XopBean xopOriginal, XopBean xopResponse) {
          if (!Arrays.equals(xopResponse.getBytes(), xopOriginal.getBytes())) {
              throw new RuntimeException("Received XOP attachment is corrupted");
          }
          System.out.println();
          System.out.println("XOP attachment has been successfully received");
      }
docs: Verifies that the received image is identical to the original one.
  @param xopOriginal
  @param xopResponse