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Calling Rest API in java from Hackerrank IDE

I was trying to call an api like below. It works in my IDE(Intellij), where as it fails in hackerrank IDE while getting input stream.
import java.io.*;
import java.util.*;
import java.net.*;
URL url = new URL("https://jsonmock.hackerrank.com/api/article_users?page=1");
HttpURLConnection connection = (HttpURLConnection)url.openConnection();
connection.setRequestMethod("GET");
connection.addRequestProperty("Content-Type", "application/json");
InputStream is = connection.getInputStream();
Getting an error:
error while calling: java.net.UnknownHostException: jsonmock.hackerrank.com
inside hacker rank IDE.
Please let me know your suggestions

just remove s from https
URL url = new URL("http://jsonmock.hackerrank.com/api/article_users?page=1");

Are you sure Hackerrank IDE has api call feature?
Perhaps for security or some other reason, this feature may be blocked or not supported.

It may be the case that Hackerrank does not let Java code make outbound network requests. Similar questions here and here suggest that you may need to choose a different language that Hackerrank supports. I imagine they should list it somewhere on their site, or on the IDE page directly.

Consumption of a REST web service using URLConnection

I am trying to consume a RESTFUL web service using Java(HttpURLConnection and InputStream).I am able to print the response using BufferedReader, but it returns a response header as well and the format is causing issues to convert it to a Java POJO.
I tried using a URLConnection and then retrieving the input stream and passing it to the ObjectMapping(provided by Jackson)
final URL url = new URL("url");
final HttpURLConnection uc = (HttpURLConnection) url.openConnection();
uc.setRequestMethod("GET");
final ObjectMapper objectMapper = new ObjectMapper();
MyData myData = objectMapper.readValue(uc.getInputStream(), MyData.class);
Error Message : "No content to map due to end-of-input\n"

In your code you don't show where you actually read the data and where you declared and filled your output variable. As code is now it seems to be the incorrect reading from your rest service. But instead of writing your own code to read fro rest url I would suggest to use the 3d party library that does it for you. Here is few suggestions: Apache Http Client, OK Http client and finally my favorite - MgntUtils Http Client (library written and maintained by me) Here is the HttpClient javadoc, Here is the link to The latest Maven artifacts for MgntUtils library and here MgntUtils Github link that contains library itself with sources and javadoc. Choose some Http Client and read the content using that client and then you can use the content.

setting content type in rest assured

I'm trying to invoke a rest call using rest assured. My API accepts, "application/json" as content type and I need to set in the call. I set the content type as mentioned below.
Option 1
Response resp1 = given().log().all().header("Content-Type","application/json")
.body(inputPayLoad).when().post(addUserUrl);
System.out.println("Status code - " +resp1.getStatusCode());
Option 2
Response resp1 = given().log().all().contentType("application/json")
.body(inputPayLoad).when().post(addUserUrl);
The response I get is "415" (indicates that "Unsupported media type ").
I tried invoking the same api using plain java code and it works. For some mysterious reason, I cudn't get it working through RA.
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost(addUserUrl);
StringEntity input = new StringEntity(inputPayLoad);
input.setContentType("application/json");
post.setEntity(input);
HttpResponse response = client.execute(post);
System.out.println(response.getEntity().getContent());
/*
BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
String line = "";
while ((line = rd.readLine()) != null) {
System.out.println("Output -- " +line);
}

I faced similar issue while working with rest-assured 2.7 version. I tried setting both the contentType and also accept to application/json but it didn't work. Adding carriage feed and new line characters at the end as the following worked for me.
RestAssured.given().contentType("application/json\r\n")
The API seems to be missing to add new line characters after Content-Type header due to which the server is not able to differentiate between the media type and the rest of the request content and hence throwing the error 415 - "Unsupported media type".

Here is the complete POST example using CONTENT_TYPE as JSON.
import io.restassured.http.ContentType;
RequestSpecification request=new RequestSpecBuilder().build();
ResponseSpecification response=new ResponseSpecBuilder().build();
#Test
public void test(){
User user=new User();
given()
.spec(request)
.contentType(ContentType.JSON)
.body(user)
.post(API_ENDPOINT)
.then()
.statusCode(200).log().all();
}

Give a try
given().contentType(ContentType.JSON).body(inputPayLoad.toString)

This might possibly be the case with your test. Try this.
https://github.com/rest-assured/rest-assured/wiki/Usage#avoid-adding-the-charset-to-content-type-header-automatically
Avoid adding the charset to content-type header automatically
By default REST Assured adds the charset header automatically. To
disable this completely you can configure the EncoderConfig like this:
RestAssured.config = RestAssured.config(config().encoderConfig(encoderConfig().appendDefaultContentCharsetToContentTypeIfUndefined(false));

As mentioned in previous posts there is a method:
RequestSpecification.contentType(String value)
I did not work for me too. But after upgrade to the newest version (in this moment 2.9.0) it works. So please upgrade :)

I was facing something similar and after some time we noticed the problem was actually coming from the server side. Please check your call on Postman and see if when it's triggered you need to change it from HTML to JSON. If you need to do that, the backend may need to force the response to be in JSON format by adding its content type. Even if it's encoded in JSON you're still may need to do that.
Thats the line of code we added:
header('Content-type:application/json;charset=utf-8');
.
public function renderError($err){
header('Content-type:application/json;charset=utf-8');
echo json_encode(array(
'success' => false,
'err' => $err
));
}
And that's what was happening on the backend:
Hope that can help somehow. :)

import io.restassured.RestAssured;
import io.restassured.http.ContentType;
import static org.hamcrest.Matchers.is;
import org.testng.annotations.Test;
import static io.restassured.RestAssured.given;
public class googleMapsGetLocation {
#Test
public void getLocation() {
RestAssured.baseURI = "https://maps.googleapis.com";
given().param("location", "-33.8670522,151.1957362")
.param("radius", "500")
.param("key", "AIzaSyAONLkrlUKcoW-oYeQjUo44y5rpME9DV0k").when()
.get("/maps/api/place/nearbysearch/json").then().assertThat()
.statusCode(200).and().contentType(ContentType.JSON)
.body("results[0].name", is("Sydney"));
}
}

For your First option can you please try adding this header too and sending the request?
.header("Accept","application/json")

HttpClient ignoring encoding, on a single computer

I am using HttpClient (version 3.1) on several different (but apparently identical) computers to read a UTF-8 encoded JSON data from a URL.
On all the machines, save one, it works fine. I have some Spanish language words and they come through with accents and tildes intact.
One computer stubbornly refuses to cooperate. It is apparently treating the data as ISO-8859-1, despite a Content-Type: application/json;charset=utf-8 header.
If I use curl to access that URL from that computer, it works correctly. On every other computer, both curl and my HttpClient-based program work correctly.
I did an md5sum on the common-httpclient.jar file on each machine: the same.
Is there some setting, deep in Linux, that might be different and be messing with me? Any other theories, or even places to look?
EDIT: some people asked for more details.
Originally I had the problem deep in the bowels of a complex Tomcat app, but I lightly adapted the sample to just retrieve the URL in question, and (fortunately) had the same problem.
These are Linux 2.6 machines running jdk1.7.0_45.
An env command yields a bunch of variables. The only one that looks remotely on point is LANG=en_US.UTF-8.

How do you get the json response data from HttpClient?
If you get it back in binary form (through getResponseBodyAsStream() for example), and then convert it to a String without specifying charset, then the result depends on your JVM's default charset.
You can check the value of JVM default charset by:
Charset.defaultCharset().name()
This might give "UTF-8" on all machines except the one failing.

Without seeing your code, it is difficult to say what's wrong, but here is a "correct" way of doing this (using HttpClient 3.1.0 for request and Jackson 2.1.3 to parse the JSON).
import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.http.HttpStatus;
import java.io.IOException;
import java.io.InputStreamReader;
HttpClient hc = new HttpClient();
GetMethod get = new GetMethod(uri);
int status = hc.executeMethod(get);
if (status != HttpStatus.SC_OK) throw new RuntimeException("http status " + status);
ObjectMapper jsonParser = new ObjectMapper(new JsonFactory());
// we use an InputStreamReader with explicit charset to read the response body
JsonNode json = jsonParser.readTree(
new InputStreamReader(get.getResponseBodyAsStream(), get.getResponseCharSet())
);

I already faced this issue and this was because of the encoding type configured in the client. So I had to make a "work around" like the one below:
String encmsg = new String(respStr.getBytes("ISO-8859-1"), java.nio.charset.Charset.forName("UTF-8"));
It reads the String as ISO-8859-1 and convert to UTF-8.

How can post data to form which is in other server

Iam creating automated system to post the data to the form for registering into the web site
URL url = new URL("https://www.walmart.com/subflow/YourAccountLoginContext/1471476370/sub_generic_login/create_account.do");
String postData = "firstName="+xlsDataList.get(0)+"&lastName="+xlsDataList.get(1)+"&userName="+xlsDataList.get(2)+"&userNameConfirm="+xlsDataList.get(3)+"&pwd="+xlsDataList.get(5)+"&pwdConfirm="+xlsDataList.get(6);
HttpsURLConnection uc = (HttpsURLConnection) url.openConnection();
uc.setDoInput(true);
uc.setDoOutput(true);
uc.setRequestMethod("POST");
uc.setRequestProperty("Accept", "*/*");
uc.setRequestProperty("Content-Length", Integer.toString(postData.getBytes().length));
uc.setRequestProperty("Content-Type", "text/html; charset=utf-8");
OutputStreamWriter outputWriter = new OutputStreamWriter(uc.getOutputStream());
outputWriter.write(postData);
outputWriter.flush();
outputWriter.close();
I thought that those above postdata are just request attributes , and coded accordingly. But after closely checking the view source, i came to know that those are form attributes.
I dnt have access to that form. Now how can i post the data to the form, so that the user get registered by the site?
i have to set the values to formbean.
Please provide your suggesions.

Your are using the wrong Content-Type in your POST: you need to use application/x-www-form-urlencoded. Once you change that, the server will interpret your request body as request parameters and (likely) your "formbean" will be filled with the data.
The above code may be a test case, but you really ought to take care to properly encode all of your data that you are trying to POST. Otherwise, you run the risk of either having a syntactically invalid request (in which case, the server will either reject the request, or ignore important parameters) or introducing a security vulnerability where a user can inject arbitrary request parameters into your POST. I highly recommend code that looks like this:
import java.net.URLEncoder;
String charset = "UTF-8"; // Change this if you want some other encoding
StringBuilder postData = new StringBuilder();
postData.append(URLEncoder.encode("firstName", charset));
postData.append("=");
postData.append(URLEncoder.encode(xlsDataList.get(0)), charset);
postData.append("&");
postData.append(URLEncoder.encode("lastName", charset));
postData.append("=");
postData.append(URLEncoder.encode(xlsDataList.get(1), charset));
postData.append("&");
postData.append(URLEncoder.encode("userName", charset));
postData.append("=");
postData.append(URLEncoder.encode(xlsDataList.get(2), charset));
postData.append("&");
postData.append(URLEncoder.encode("userNameConfirm", charset));
postData.append("=");
postData.append(URLEncoder.encode(xlsDataList.get(3), charset));
postData.append("&");
postData.append(URLEncoder.encode("pwd", charset));
postData.append("=");
postData.append(URLEncoder.encode(xlsDataList.get(5), charset));
postData.append("&");
postData.append(URLEncoder.encode("pwdConfirm", charset));
postData.append("=");
postData.append(xlsDataList.get(6), charset));
It seems silly to encode the static strings like "userNameConfirm", but if you get into that habit, you'll end up using it all the time and your code will be a lot safer.
Also, you need to make sure that the data you send through the OutputStream has the right Content-Length: you are computing the content-length properly, but then you aren't using the bytes you used for the computation to send to the client. You want your code to look more like this:
byte[] postDataBytes = postData.getBytes(charset);
uc.setRequestProperty("Content-Length", Integer.toString(postDataBytes.length));
uc.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
OutputStream outputStream = uc.getOutputStream();
outputStream.write(postDataBytes);
outputStream.flush();
outputStream.close();
You can find a very comprehensive HTTPUrlConnection tutorial in the community wiki: Using java.net.URLConnection to fire and handle HTTP requests

I recommend to use Apache HttpClient. its faster and easier to implement.
PostMethod post = new PostMethod("https://www.walmart.com/subflow/YourAccountLoginContext/1471476370/sub_generic_login/create_account.do");
NameValuePair[] data = {
new NameValuePair("firstName", "joe"),
new NameValuePair("lastName", "bloggs")
};
post.setRequestBody(data);
InputStream in = post.getResponseBodyAsStream();
// handle response.
For details you can refer http://hc.apache.org/

If your project uses Spring 3.x or later I would recommend using the Spring RestTemplate its pretty handy for doing http, code below will log do a form post.
public String login(String username, String password)
{
MultiValueMap<String, String> form = new LinkedMultiValueMap<>();
form.add(usernameInputFieldName, username);
form.add(passwordInputFieldName, password);
RestTemplate template = new RestTemplate();
URI location = template.postForLocation(loginUrl(), form);
return location.toString();
}

The "HTTP Error 500" you've described in your comment is an "Internal server error".
This means that the server either can't use your request (GET/POST) or there's a problem specific to the server you are trying to call.
Taking a look at the URL you're calling, I immediately the same Error 500.
Same happens for both GET and POST requests at httqs://www.walmart.com/subflow/YourAccountLoginContext/1471476370/sub_generic_login/create_account.do (Live link deactivated; replace "q" with "p" to make it work.)
In short: the generally returned "HTTP Error 500" from WallMart's servers prevents your call to succeed.
By the way:
It's not uncommon to get an error 500 instead of a 403 if they are locking your access down.
As you probably don't own the WallMart website and since you're trying to access levels of their websites that are worth to be protected from 3rd party acces, this might well be the case. ;)
PS: I'm not sure if it's wise to show the AccountLogin number in public like this. After all, it's the client ID of a specific WallMart account holder. But hey, that's your choice, not mine.

Also, double check the parameters you are sending. There may be some validations on input data the server is doing. Eg, some fields are mandatory, some are numbers only, etc.

Try spoofing as a browser by modifying the User Agent. WalMart may have a security mechanism that detects that you are doing this in an automated way.
(If you have problems setting the user agent see this post: Setting user agent of a java URLConnection)