Java requests to Microsoft Graph API perform ok but return 500

I have a small Java program with 3 methods:

• one for getting the token from graph api for authentication bearer token. This is ok, token is ok and returns 200 http
• the other two are for creating a user in Azure AD and assigning an licences.
  Taking the first, creating the user. The token is ok, the user is created, and authentication on platform works fine(password is set ok). BUT on response I get 500 http even task is done correctly in AzureAD. If I place same request in PowerShell there is no problem, no error. Please help me with an advice. My method for creating user is:

public static String createUser(String token) {
String user = "{\n"
+ "  \"accountEnabled\": true,\n"
+ "  \"displayName\": \"displayName-value\",\n"
+ "  \"mailNickname\": \"mailNickname-value\",\n"
+ "  \"userPrincipalName\": \"upn@microsoft.ro\",\n"
+ "  \"passwordProfile\" : {\n"
+ "    \"forceChangePasswordNextSignIn\": false,\n"
+ "    \"password\": \"Complexity2021\"\n"
+ "  },\n"
+ " \"usageLocation\" : \"RO\""
+ "}";
HttpURLConnection conn = null;
URL url = null;
try {
url = new URL("https://graph.microsoft.com/beta/users");
conn = (HttpURLConnection) url.openConnection();
conn.setDoOutput(true);
conn.setRequestMethod("POST");
conn.setRequestProperty("Content-Type", "application/json");
conn.setRequestProperty("Authorization", "Bearer " + token);
conn.setDoOutput(true);
conn.setRequestMethod("POST");
conn.connect();
OutputStream os = conn.getOutputStream();
os.write(user.getBytes());
os.flush();
int status = conn.getResponseCode();
System.out.println(status); // 500!!!!! AND THE USER is ok in AzureAD
switch (status) {
case 200:
case 201:
BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
StringBuilder sb = new StringBuilder();
String line;
while ((line = br.readLine()) != null) {
sb.append(line + "\n");
}
br.close();
return sb.toString();
}
} catch (Exception ex) {
ex.printStackTrace();
} finally {
if (conn != null) {
try {
conn.disconnect();
} catch (Exception ex1) {
ex1.printStackTrace();
}
}
}
return null;
}

Thanks for reply, I was checked the errorStream and was containing:

{
"error": {
"code": "InternalServerError",
"message": "The MIME type 'text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2' requires a '/' character between type and subtype, such as 'text/plain'.",
"innerError": {
" 
}
}
}

The solution was:

conn.setRequestProperty("Accept", "application/json");

Thank you!

You are ignoring the error data returned by the server - but, according to the documentation, it should explain the cause of the 500 status. Suggested code:

        // ...
System.out.println(status); // 500!!!!! AND THE USER is ok in AzureAD
// always reads server response
StringBuilder sb = new StringBuilder();
try (BufferedReader br = 
new BufferedReader(new InputStreamReader(conn.getInputStream())) {
String line;
while ((line = br.readLine()) != null) {
sb.append(line + "\n");
}
} // <-- br is automatically closed here!
String output = sb.toString();
if (status == 200 || status == 201) {
return output;
} else {
// choose a suitable exception, or return null but log error
throw new FooException("Received error " + status + 
" while doing Foo; details follow: " + output);
}
// ... 

I also suggest replacing all your try { } finally { } that free resources with try-with-resources versions -- they are safer (always closing acquired resources) and more readable.