Not able to import Jsonbject and when I do I get an error

not sure what I'm doing wrong here, please. even when I import I get JSONObject cannot be resolved to a type. error here "final JSONObject json = new JSONObject();" and object cannot be resolved here "final String jsonString = obj.toString();"

package maven;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

// import org.apache.http.client.HttpClient;
// import org.apache.http.client.methods.HttpPost;
// import org.apache.http.entity.StringEntity;
// import org.apache.http.HttpResponse;
// import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellType;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.json.simple.JSONObject;

    final JSONObject json = new JSONObject();
        json.put("id", "uuuu@mail.edu");
        json.put("name", "Jon doe");
        json.put("average", calculateClassAverage(students));
        json.put("studentIds", femaleIDs.toArray());
        
        final URL url = new URL ("http:weblink"); 
        final HttpURLConnection con = (HttpURLConnection) url.openConnection();
        con.setRequestMethod("POST");
        con.setDoOutput(true);
        con.setRequestProperty("Content-Type", "application/json; utf-8");
        con.setRequestProperty("Accept", "application/json");

        final String jsonString = obj.toString();
        System.out.println("JSON Request String: ");
        System.out.println(jsonString);

The issue JSONObject cannot be resolved to a type is probably because you haven't import the library correctly. The class JSONObject seems to belong to the library org.json. So if you use Maven or Gradle, import it as described in the link.

The issue with this line:

final String jsonString = obj.toString();

Is because the variable obj is not defined in your code. Maybe you mean:

final String jsonString = json.toString();