How to fix http response code 400 error in java ? Is there any malformed request syntax or invalid request message framing?

Samuel I :

I created a ML model in IBM Watson Studio, and deployed the model into web-service. I need to create a java program which sends input and retrieves output from that web-service.
I checked all my connectivity credentials there was no problem in that.
The code which i'm using here is the same code given in watson-studio (in implementation tab under deployment section) still i'm getting error.
The program stops at this line

scoringBuffer = new BufferedReader(new InputStreamReader(scoringConnection.getInputStream()));

Check this code :-

package Original;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.util.Base64;
import java.util.HashMap;
import java.util.Map;

public class Iris_Deployment {

    public static void main(String[] args) {
        // NOTE: you must manually construct wml_credentials hash map below
        // using information retrieved from your IBM Cloud Watson Machine Learning Service instance.

        Map<String, String> wml_credentials = new HashMap<String, String>()
        {{
            put("url", "https://eu-gb.ml.cloud.ibm.com");
            put("username", "my-username-comes-here");
            put("password", "my-password-comes-here");
        }};

        String wml_auth_header = "Basic " +
                Base64.getEncoder().encodeToString((wml_credentials.get("username") + ":" +
                        wml_credentials.get("password")).getBytes(StandardCharsets.UTF_8));
        String wml_url = wml_credentials.get("url") + "/v3/identity/token";
        HttpURLConnection tokenConnection = null;
        HttpURLConnection scoringConnection = null;
        BufferedReader tokenBuffer = null;
        BufferedReader scoringBuffer = null;
        try {
            // Getting WML token
            URL tokenUrl = new URL(wml_url);
            tokenConnection = (HttpURLConnection) tokenUrl.openConnection();
            tokenConnection.setDoInput(true);
            tokenConnection.setDoOutput(true);
            tokenConnection.setRequestMethod("GET");
            tokenConnection.setRequestProperty("Authorization", wml_auth_header);
            tokenBuffer = new BufferedReader(new InputStreamReader(tokenConnection.getInputStream()));
            StringBuffer jsonString = new StringBuffer();
            String line;
            while ((line = tokenBuffer.readLine()) != null) {
                jsonString.append(line);
            }

            // Scoring request
            URL scoringUrl = new URL("https://eu-gb.ml.cloud.ibm.com/v3/wml_instances/3c523ca2-c5b5-409f-9773-7634c8bc5144/deployments/80b8046d-84e0-4081-a770-d10099c4a378/online");
            String wml_token = "Bearer " +
                    jsonString.toString()
                            .replace("\"","")
                            .replace("}", "")
                            .split(":")[1];
            scoringConnection = (HttpURLConnection) scoringUrl.openConnection();
            scoringConnection.setDoInput(true);
            scoringConnection.setDoOutput(true);
            scoringConnection.setRequestMethod("POST");
            scoringConnection.setRequestProperty("Accept", "application/json");
            scoringConnection.setRequestProperty("Authorization", wml_token);
            scoringConnection.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
            OutputStreamWriter writer = new OutputStreamWriter(scoringConnection.getOutputStream(), "UTF-8");

            // NOTE: manually define and pass the array(s) of values to be scored in the next line
            String payload = "{\"fields\": [\"SepalLengthCm\", \"SepalWidthCm\", \"PetalLengthCm\", \"PetalWidthCm\"], \"values\": [{1.2, 1.3, 2.2, 2.3}]}";
            writer.write(payload);
            writer.close();

            scoringBuffer = new BufferedReader(new InputStreamReader(scoringConnection.getInputStream()));
            StringBuffer jsonStringScoring = new StringBuffer();
            String lineScoring;
            while ((lineScoring = scoringBuffer.readLine()) != null) {
                jsonStringScoring.append(lineScoring);
            }
            System.out.println(jsonStringScoring);
        } catch (IOException e) {
            System.out.println("The URL is not valid.");
            e.printStackTrace();
        }
        finally {
            if (tokenConnection != null) {
                tokenConnection.disconnect();
            }
            if (tokenBuffer != null) {
                try {
                    tokenBuffer.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (scoringConnection != null) {
                scoringConnection.disconnect();
            }
            if (scoringBuffer != null) {
                try {
                    scoringBuffer.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

Error :-

The URL is not valid.
java.io.IOException: Server returned HTTP response code: 400 for URL: https://eu-gb.ml.cloud.ibm.com/v3/wml_instances/3c523ca2-c5b5-409f-9773-7634c8bc5144/deployments/80b8046d-84e0-4081-a770-d10099c4a378/online
    at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1913)
    at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1509)
    at java.base/sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:245)
    at Original.Iris_Deployment.main(Iris_Deployment.java:71)

Process finished with exit code 0

Chris Jones :

Please try passing your scoring payload as follows:

\"values\": [[1.2, 1.3, 2.2, 2.3]]

(replacing the inner "{" with "[")