'URLjava.io.IOException: Server returned HTTP response code: 411 in JAVA

I'm checking whether internet is available or not 

URL url = new URL("http://www.google.co.in/");
            final HttpURLConnection conn = (HttpURLConnection) url.openConnection();

            // set connect timeout.
            conn.setConnectTimeout(1000000);

            // set read timeout.
            conn.setReadTimeout(1000000);

            conn.setRequestMethod("POST");

            conn.setRequestProperty("Content-Type","text/xml");

            conn.setDoOutput(true);

            conn.connect();

            Integer code = conn.getResponseCode();
            final String contentType = conn.getContentType();

While running this code i'm getting the exception

URLjava.io.IOException: Server returned HTTP response code: 411

What could be the error.

java


Solution 1:[1]

Try to add the following lines to your code, that might help you understand the problem a bit better : 

 conn.setRequestProperty("Content-Length", "0");

Do check what your inputStream from your HTTP ERROR 411 states by adding this code : 

InputStream is = null;
if (conn.getResponseCode() != 200) 
{
    is = conn.getErrorStream();
} 
else 
{
    is = conn.getInputStream();
}

Hopefully that might help.

Regards

Solution 2:[2]

411 - Length Required

The 411 status code occurs when a server refuses to process a request because a content length was not specified.

refer for details

Solution 3:[3]

Adding the following line in the code where post is performed worked:

conn.setRequestProperty("Content-Length", "0");

Solution 4:[4]

POST/ PUT should be use when modifying or creating a new instance on the back-end. When using REST call in the form on http://///{parameter1}/{parameter2} (and so on), no query or body send! still it should be POST call if it modifying the data.

So, in this case we can do some Reflection.

String urlParameters = url.getQuery();
if (urlParameters == null) urlParameters = "";

byte[] postData = urlParameters.getBytes(StandardCharsets.UTF_8);
int postDataLength = postData.length;
if (postDataLength > 0) {
//in case that the content is not empty
        conn.setRequestProperty("Content-Length", Integer.toString(postDataLength));
    } else {
        // Reflaction the HttpURLConnectioninstance
        Class<?> conRef = conn.getClass();
        // Fetch the [requests] field, Type of MessageHeader 
        Field requestsField= conRef .getDeclaredField("requests");
        // The [requests] field is private, so we need to allow accessibility
        requestsField.setAccessible(true);
        MessageHeader messageHeader = (MessageHeader) requestsField.get(conn);
       // Place the "Content-Length" header with "0" value
        messageHeader.add("Content-Length", "0");
       // Inject the modified headers
        requestsField.set(conn, messageHeader);
    }

In this way we don't harm the existing model and the call will be sent with the ZERO length header.

Solution 5:[5]

I passed an empty object "{}" in the body this fixed it.

HttpURLConnection connection = (HttpURLConnection) new URL(urlString).openConnection();
connection.setRequestMethod("POST");
connection.setRequestProperty("Content-Type","application/json");
OutputStreamWriter writers = new OutputStreamWriter(connection.getOutputStream());
writers.write("{}"); //body
writers.flush();

instead of this you can set Content-length as 0 also as suggested in other answers.

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 nIcE cOw
Solution 2 Hemant Metalia
Solution 3 Dibyendu Mitra Roy
Solution 4 Amour Shmuel
Solution 5 MOHANTEJA

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