How to send audio file to server via POST request in Java (Android App)?

I want to send an audio file to a server via a POST request in my Java Android App. The following code is what I currently have, however, it is not working.

I have found this class implementing a MultiPart Utility:

public class MultipartUtility {
private static final String LINE_FEED = "\r\n";
private HttpURLConnection httpConn;
private String charset;
private OutputStream outputStream;
private PrintWriter writer;
private final String boundary;
public MultipartUtility(String requestURL, String charset)
throws IOException {
this.charset = charset;
// creates a unique boundary based on time stamp
boundary = "===" + System.currentTimeMillis() + "===";
URL url = new URL(requestURL);
httpConn = (HttpURLConnection) url.openConnection();
httpConn.setUseCaches(false);
httpConn.setDoOutput(true); // indicates POST method
httpConn.setDoInput(true);
httpConn.setRequestProperty("Content-Type",
"multipart/form-data; boundary=" + boundary);
httpConn.setRequestProperty("User-Agent", "CodeJava Agent");
httpConn.setRequestProperty("Test", "Bonjour");
outputStream = httpConn.getOutputStream();
writer = new PrintWriter(new OutputStreamWriter(outputStream, charset),
true);
}
public void addFormField(String name, String value) {
writer.append("--" + boundary).append(LINE_FEED);
writer.append("Content-Disposition: form-data; name=\"" + name + "\"")
.append(LINE_FEED);
writer.append("Content-Type: text/plain; charset=" + charset).append(
LINE_FEED);
writer.append(LINE_FEED);
writer.append(value).append(LINE_FEED);
writer.flush();
}
public void addFilePart(String fieldName, File uploadFile)
throws IOException {
String fileName = uploadFile.getName();
writer.append("--" + boundary).append(LINE_FEED);
writer.append(
"Content-Disposition: form-data; name=\"" + fieldName
+ "\"; filename=\"" + fileName + "\"")
.append(LINE_FEED);
writer.append(
"Content-Type: "
+ URLConnection.guessContentTypeFromName(fileName))
.append(LINE_FEED);
writer.append("Content-Transfer-Encoding: binary").append(LINE_FEED);
writer.append(LINE_FEED);
writer.flush();
FileInputStream inputStream = new FileInputStream(uploadFile);
byte[] buffer = new byte[4096];
int bytesRead = -1;
while ((bytesRead = inputStream.read(buffer)) != -1) {
outputStream.write(buffer, 0, bytesRead);
}
outputStream.flush();
inputStream.close();
writer.append(LINE_FEED);
writer.flush();
}
public void addHeaderField(String name, String value) {
writer.append(name + ": " + value).append(LINE_FEED);
writer.flush();
}
public List<String> finish() throws IOException {
List<String> response = new ArrayList<String>();
writer.append(LINE_FEED).flush();
writer.append("--" + boundary + "--").append(LINE_FEED);
writer.close();
// checks server's status code first
int status = httpConn.getResponseCode();
if (status == HttpURLConnection.HTTP_OK) {
BufferedReader reader = new BufferedReader(new InputStreamReader(
httpConn.getInputStream()));
String line = null;
while ((line = reader.readLine()) != null) {
response.add(line);
}
reader.close();
httpConn.disconnect();
} else {
throw new IOException("Server returned non-OK status: " + status);
}
return response;
}
}

and want to send a POST request to a server with this client code:

String requestURL = "http://0.0.0.0:5000/test";
try {
com.eng.elfarsisy.recored.MultipartUtility multipart = new com.eng.elfarsisy.recored.MultipartUtility(requestURL, charset);
multipart.addHeaderField("User-Agent", "CodeJava");
multipart.addHeaderField("Test-Header", "Header-Value");
multipart.addFormField("description", "Cool Pictures");
multipart.addFormField("keywords", "Java,upload,Spring");
multipart.addFilePart("fileUpload", uploadFile1);
List<String> response = multipart.finish();
System.out.println("SERVER REPLIED:");
for (String line : response) {
System.out.println(line);
}
} catch (IOException ex) {
System.err.println(ex);
}

However I am getting this response:

I/System.out: (HTTPLog)-Static: isSBSettingEnabled false
I/System.out: (HTTPLog)-Static: isSBSettingEnabled false
W/System.err: java.net.SocketException: Permission denied

How can I fix this? Any ideas would be greatly appreciated.

Have you added this permission to your manifest?

<uses-permission android:name="android.permission.INTERNET"/>