Ondrej Tokar Ondrej Tokar - 1 year ago 113
HTTP Question

Delete request from custom Java client acts differently than e.g. Postman

I have a java application that is making an HTTP DELETE to an external REST service. This error gets back to me from the server (running C#):

"Value cannot be null.\r\nParameter name: source\n at System.Linq.Enumerable.Count[TSource](IEnumerable`1 source)\r\n at AppCloud_Framework.Controllers.NotificationItemsController.DeleteNotificationItem(NotificationItem[] notificationItems) in C:\\Users\\jonas\\OneDrive\\VS Projects\\AppCloud Framework\\AppCloud Framework\\Controllers\\NotificationItemsController.cs:line 101\nValue:null"

The thing is, when I setup Postman to make the HTTP request to the same URL, with the same Payload and same HTTP method, the action is successful.

I do not have access to the server to investigate further so I need to find the resolution from the client side. Anyway it appears to be a client side issue.

I've been trying to find the problem myself but haven't succeeded. All I could come up with was to add "application/json" to Accept and Content-Type header properties.

My HTTP client:

public static Response execute(String url, Method method, String body) {
Response response = new Response();

try {
// Create a trust manager that does not validate certificate chains
TrustManager[] trustAllCerts = new TrustManager[] { new X509TrustManager() {
public java.security.cert.X509Certificate[] getAcceptedIssuers() {
return null;
public void checkClientTrusted(X509Certificate[] certs, String authType) {
public void checkServerTrusted(X509Certificate[] certs, String authType) {
} };
// Install the all-trusting trust manager
final SSLContext sc = SSLContext.getInstance("SSL");
sc.init(null, trustAllCerts, new java.security.SecureRandom());
// Create all-trusting host name verifier
HostnameVerifier allHostsValid = new HostnameVerifier() {
public boolean verify(String hostname, SSLSession session) {
return true;

// Install the all-trusting host verifier


URL urlObj = new URL(url);
HttpsURLConnection conn = (HttpsURLConnection) urlObj.openConnection();

conn.setRequestProperty("Content-Type", "application/json");
conn.setRequestProperty("Accept", "application/json");
//conn.setRequestProperty("Authorization", _authToken);

if (method == Method.POST || method == Method.PUT || method == Method.DELETE) {
final OutputStream os = conn.getOutputStream();

int status = conn.getResponseCode();
//log.info("HTTP request status code: "+status);
InputStream is;
if (status>399){
is = conn.getErrorStream();
is = conn.getInputStream();
if (is==null) return null;
BufferedReader rd = new BufferedReader(new InputStreamReader(is,

String line;
while ((line = rd.readLine()) != null) {
response.body += line;

response.statusCode = conn.getResponseCode();
} catch (Exception e) {
response.exception = e.getMessage();
return response;

I am making a request with this body(disregard the encoding issue, source of that is somewhere else):

[{"hash":"150a17e99f67ce29fcc600c92eee831d","instanceid":"cb440a6f-44ef-4f05-ab41-143153655b6e","text":"{\"C_FirstAndLastName\":\"und\",\"ContactID\":\"1374231\",\"C_Fax\":\"\"}","queueDate":"2016-10-04T03:18:37"},{"hash":"1a94d9b5acff1a27dfe45be4ca5d9138","instanceid":"fdsfdsf-44ef-4f05-ab41-143153655b6e","text":"{\"C_FirstAndLastName\":\"J?รข??rgen\",\"ContactID\":\"323093\",\"C_Fax\":\"fsdfsd-B401-4AD3-AEA1-fdsfsdfsd\"}","queueDate":"2016-10-04T03:18:37"},{"hash":"8e592fb16d464bfd0f90f69818944198","instanceid":"fdsfsdf-44ef-4f05-ab41-143153655b6e","text":"{\"C_FirstAndLastName\":\"Claus\",\"ContactID\":\"2495844\",\"C_Fax\":\"fdsfsdgsd-304D-4E91-8586-fsdfsdfsd\"}","queueDate":"2016-10-04T03:18:37"},{"hash":"d6d226255e62690e50abbfa15c4b5462","instanceid":"cb440a6f-44ef-4f05-ab41-143153655b6e","text":"{\"C_FirstAndLastName\":\"Test J??rgen\",\"ContactID\":\"323093\",\"C_Fax\":\"fdsfsdfsd-B401-4AD3-AEA1-fdsfsdfsdf\"}","queueDate":"2016-10-04T03:18:49"}]

Answer Source

All I had to do was to define encoding in the output stream. Not sure if anyone could help me with that as I have just tried many things and some of it worked, but unfortunately nothing was pointing me into this direction.

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