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Why the file I download via GitHub API has no content?

I am using the GitHub API to fetch files from a repository. I have the functionality implemented and it does work, I download the needed files but I found something strange, out of the 4 files I get, one is empty (no content inside) even though when I go the to repository and open it there it is clearly with content. The rest of the files have their content in when downloaded. Any idea why that happens?
Here is my code:
public int downloadFromGithub(String repo, String fileName) throws IOException {
URL url = new URL(repo);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setDoInput(true);
connection.setRequestProperty("Authorization", ****);
connection.setRequestProperty("Accept", ****);
if (connection.getResponseCode() == HttpURLConnection.HTTP_OK && fileName!=null)
{
return saveFile(connection, fileName);
}
else { return connection.getResponseCode();}
}
public void downloadMultipleFilesFromGithub(String repo,String directoryPath) throws IOException {
URL url = new URL(repo);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setDoInput(true);
connection.setRequestProperty("Authorization", *****);
connection.setRequestProperty("Accept", "***");
String response = getResponseBody(connection);
try {
JSONObject jsonObj = new JSONObject(response);
JSONArray array = jsonObj.getJSONArray("tree");
for (int i=0; i < array.length(); i++) {
System.out.println(array.getJSONObject(i).get("path"));
String path = array.getJSONObject(i).get("path").toString();
if(path.contains("Scripts")){
String fileName = path.replace(scriptsDirectoryReplace, "");
downloadFromGithub(scriptsRepositoryDirectory+fileName,fileName);
}
}
} catch (JSONException e) {
throw new RuntimeException(e);
}
}
public String getResponseBody(HttpURLConnection conn) {
BufferedReader br = null;
StringBuilder body = null;
String line = "";
try {
br = new BufferedReader(new InputStreamReader(
conn.getInputStream()));
body = new StringBuilder();
while ((line = br.readLine()) != null)
body.append(line);
return body.toString();
} catch (Exception e) {
throw new RuntimeException(e);
}
}
public int saveFile(HttpURLConnection connection, String fileName) throws IOException {
// opens input stream from the HTTP connection
String saveFilePath = fileSaveDirectory + File.separator + fileName;
// opens an output stream to save into file
FileOutputStream writer = new FileOutputStream(saveFilePath);
InputStream reader = connection.getInputStream();
int bytesRead;
byte[] buffer = new byte[4096];
while ((bytesRead = reader.read(buffer)) != -1) {
writer.write(buffer, 0, bytesRead);
}
reader.close();
writer.close();
return connection.getResponseCode();
}

Json Result from News API is null

#Override
protected String doInBackground(String... strings) {
String result = HttpRequest.getExecute("http://newsapi.org/v2/everything?q=bitcoin&from=2020-05-30&sortBy=publishedAt&apiKey=myAPIkey");
return result;
}
I am getting a null response on passing this URL even though the same URL when opened on the browser shows a lot of stuff. I am getting a Null Pointer Exception. Please help. Below is my HttpRequest class.
HTTPRequest Class:
public class HttpRequest {
public static String getExecute(String targetUrl)
{
URL url;
HttpURLConnection httpURLConnection = null;
try
{
url = new URL(targetUrl);
httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setRequestMethod("GET");
InputStream inputStream;
if (httpURLConnection.getResponseCode() != HttpURLConnection.HTTP_OK)
inputStream = httpURLConnection.getErrorStream();
else
inputStream = httpURLConnection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
String line;
StringBuffer response = new StringBuffer();
while ( (line = bufferedReader.readLine()) != null)
{
response.append(line);
response.append('\r');
}
bufferedReader.close();
return response.toString();
}
catch (Exception e)
{
e.printStackTrace();
return null;
}
finally {
if(httpURLConnection != null)
{
httpURLConnection = null;
}
}
}
}

You have to call connect method before reading the result or response code. Add the below line after setting up the request method
httpURLConnection.connect()

Java HttpURLConnection invoke remote server and returned 500 status

I want to invoke remote server using HttpURLConnection, here is my function:
public String invokeAwvsServer(String api, String param, String method){
System.out.println(api+param);
BufferedReader reader = null;
HttpURLConnection connection = null;
OutputStreamWriter out = null;
try {
URL url = new URL(api);
connection = (HttpURLConnection) url.openConnection();
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setUseCaches(false);
connection.setInstanceFollowRedirects(true);
connection.setRequestMethod(method);
connection.setRequestProperty("Content-Type", "application/json");
connection.setRequestProperty("X-Auth", apiKey);
connection.connect();
if(method.equalsIgnoreCase("POST")){
out = new OutputStreamWriter(connection.getOutputStream(), "UTF-8");
out.append(param);
out.flush();
}
reader = new BufferedReader(new InputStreamReader(connection.getInputStream(), "UTF-8"));
String line;
StringBuffer res = new StringBuffer();
while ((line = reader.readLine()) != null) {
res.append(line);
}
return res.toString();
} catch (IOException e) {
e.printStackTrace();
} finally {
if(reader != null){
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if(connection != null){
connection.disconnect();
}
if(out != null){
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return "error";
}
I use this function in its own class and works well, but if I call it in other class ,the remote server return 500 status code and JVM throws exception like:
java.io.IOException: Server returned HTTP response code: 500 for URL:...
What`s the reason?Thanks a lot:)

Using httpUrlConnection: am i setting up my connection correctly?

I am making use of the HttURLconnection and URLConnection api's to connect to a PHP file on my web host (x10host). However the connection does not seem to be established and no string data is sent.
I am sure that my PHP code is correct, so am I using the classes incorrectly in the below code?
#Override
protected String doInBackground(String... params) {
StringBuilder respData = new StringBuilder();
InputStream stream = null;
OutputStream os = null;
HttpURLConnection httpUrlConnection;
URLConnection conn;
URL url;
try {
url = new URL("my_url/recieveString.php");
conn = url.openConnection();
httpUrlConnection = (HttpURLConnection) conn;
httpUrlConnection.setUseCaches(false);
//httpUrlConnection.setRequestProperty("User-Agent", "App");
httpUrlConnection.setConnectTimeout(30000);
httpUrlConnection.setReadTimeout(30000);
httpUrlConnection.setRequestMethod("POST");
httpUrlConnection.setDoOutput(true);
os = httpUrlConnection.getOutputStream();
toSubmit = "test";
stream = new ByteArrayInputStream(toSubmit.getBytes(StandardCharsets.UTF_8));
copy(stream, os);
httpUrlConnection.connect();
int responseCode = httpUrlConnection.getResponseCode();
if (200 == responseCode) {
InputStream is = httpUrlConnection.getInputStream();
InputStreamReader isr = null;
try {
isr = new InputStreamReader(is);
char[] buffer = new char[1024];
int len;
while ((len = isr.read(buffer)) != -1) {
respData.append(buffer, 0, len);
}
} finally {
if (isr != null) {
isr.close();
success = true;
}
}
is.close();
} else {
// use below to get error stream
//inputStream = httpUrlConnection.getErrorStream();
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
stream.close();
os.flush();
os.close();
} catch (IOException e) {
e.printStackTrace();
}
return "done";
}
}

Exception calling an URL from a servlet

I'm trying to call an URL (URL contains only json code) from a servlet but I keep getting a read time out exceptions on getInputStream().
public class SimpleServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse esponse) throws IOException, ServletException {
BufferedReader reader = null;
StringBuilder stringBuilder;
InputStream in=null;
String json=null;
URL url = new URL("http://localhost:8080/SimpleWeb/users");
try{
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setDoInput(true);
conn.setRequestMethod("GET");
conn.setRequestProperty("Content-type", "application/json");
conn.setReadTimeout(5000);
conn.connect();
reader = new BufferedReader(new InputStreamReader(conn.getInputStream(),"UTF-8"));
stringBuilder = new StringBuilder();
String line=null;
while((line = reader.readLine()) != null){
stringBuilder.append(line + "\n");
}
json = stringBuilder.toString();
System.out.println(json);
}catch(Exception e){
System.out.println(e);
}finally{
if(reader!=null)
reader.close();
}
}
}
The code works by replacing http://localhost:8080/SimpleWeb/users with http://localhost:8080/SimpleWeb/users.txt(but only when called from a plain java app, not a servlet)
Can anyone help to see what I might be doing wrong?