Package (Java call on corvid)

Hello! I need to use WebHook in order to receive real time information from a provider (ClassMarker.com) for an "online-course-exam-tracking" purpose. The code that I need to run is shown below (provided by the provided with nice documentation in this link: https://www.classmarker.com/online-testing/api/webhooks/ ), but my only one error is the line #1, that results to relate to a "package" reserved word (see image of the error). I've been reading the forum and found in this post (https://support.wix.com/en/article/corvid-working-with-npm-packages) some information about "nmp packages" that frankly I'm not sure if it's the same thing, but presuming that IT IS the same thing, I tried to search in NPM PACKAGE library to found my provider (ClassMarker.com) with no results; So this is my question and request:

How can I make this work, and if something has to be formally requested for "evaluation" in order to add this package to the approved nmp package list, How should I proceed?

thanks a lot for your help.

package com.classmarker.webhook;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;
import java.util.Date;
import java.util.Objects;
import java.util.Enumeration;
import java.util.stream.Collectors;
import java.util.Base64;

@WebServlet("/webhook")
public class WebhookServlet extends HttpServlet {

    @Override
 protected void doPost(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws IOException {
 // You are given a uniquе secret code when crеating a Wеbhook.
        String classmarkerSecretPhrase = "YOUR_CLASSMARKER_WEBHOOK_SECRET_PHRASE";

        String jsonStringPayload = httpServletRequest.getReader().lines().collect(Collectors.joining(System.lineSeparator()));
        String headerHmacSignature = httpServletRequest.getHeader("x-classmarker-hmac-sha256");

 boolean isVerifiedSuccessfully = false;

 try {
            isVerifiedSuccessfully = verifyWebhook(jsonStringPayload, headerHmacSignature, classmarkerSecretPhrase);
        } catch (InvalidKeyException | NoSuchAlgorithmException exception) {
 // handle еxception hеre             
        }

 if (isVerifiedSuccessfully) {
            saveToFile("json_data_" + new Date() + ".json", jsonStringPayload);

 // Notify ClassMarker you have rеceived the Wеbhook.
            httpServletResponse.setStatus(HttpServletResponse.SC_OK);
        }
 else{
            httpServletResponse.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
        }

    }

 private boolean verifyWebhook(String jsonData, String headerHmacSignature, String classmarkerSecretPhrase) throws InvalidKeyException, NoSuchAlgorithmException {
 byte[] hashHMacBytes = hashHMac(jsonData, classmarkerSecretPhrase);
        String calculatedSignature = Base64.getEncoder().encodeToString(hashHMacBytes);

 return Objects.equals(headerHmacSignature, calculatedSignature);
    }

 private byte[] hashHMac(String sourceString, String key) throws InvalidKeyException, NoSuchAlgorithmException {
        String HMAC_SHA256 = "HmacSHA256";
        Mac sha512HMAC = Mac.getInstance(HMAC_SHA256);

 byte[] keyBytes = key.getBytes(StandardCharsets.US_ASCII);

        SecretKeySpec secretKeySpec = new SecretKeySpec(keyBytes, HMAC_SHA256);

        sha512HMAC.init(secretKeySpec);

 return sha512HMAC.doFinal(sourceString.getBytes(StandardCharsets.US_ASCII));
    }

 private void saveToFile(String fileName, String content) throws IOException {
        File file = new File(fileName);

        FileOutputStream fileOutputStream = new FileOutputStream(file);

 // If filе doesn't еxists, then crеate it.
 if (!file.exists()) {
            file.createNewFile();
        }

        fileOutputStream.write(content.getBytes());
        fileOutputStream.flush();
        fileOutputStream.close();
    }
}
$w.onReady(function () {
 // TODO: write your page related code here...

});