I use HttpURLConnection to do HTTP POST but I dont always get back the full response. I wanted to debug the problem, but when I step through each line it worked. I thought it must be a timing issue so I added Thread.sleep and it really made my code work, but this is only a temporary workaround. I wonder why is this happening and how to solve. Here is my code:

    URL u = new URL(url);
    URLConnection c = u.openConnection();
    InputStream in = null;
    String mediaType = null;
    if (c instanceof HttpURLConnection) {

        //c.setConnectTimeout(1000000);
        //c.setReadTimeout(1000000);

        HttpURLConnection h = (HttpURLConnection)c;
        h.setRequestMethod("POST");
        //h.setChunkedStreamingMode(-1);
        setAccept(h, expectedMimeType);
        h.setRequestProperty("Content-Type", inputMimeType);

        for(String key: httpHeaders.keySet()) {
            h.setRequestProperty(key, httpHeaders.get(key));

            if (logger.isDebugEnabled()) {
                logger.debug("Request property key : " + key + " / value : " + httpHeaders.get(key));
            }

        }

        h.setDoOutput(true);
        h.connect();

        OutputStream out = h.getOutputStream();

        out.write(input.getBytes());

        out.close();

        mediaType = h.getContentType();

        logger.debug(" ------------------ sleep ------------------ START");
        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        logger.debug(" ------------------ sleep ------------------ END");

        if (h.getResponseCode() < 400) {
            in = h.getInputStream();
        } else {
            in = h.getErrorStream();
        }

It genearates the following HTTP headers

POST /emailauthentication/ HTTP/1.1
Accept: application/xml
Content-Type: application/xml
Authorization: OAuth oauth_consumer_key="b465472b-d872-42b9-030e-4e74b9b60e39",oauth_nonce="YnDb5eepuLm%2Fbs",oauth_signature="dbN%2FWeWs2G00mk%2BX6uIi3thJxlM%3D", oauth_signature_method="HMAC-SHA1", oauth_timestamp="1276524919", oauth_token="", oauth_version="1.0"
User-Agent: Java/1.6.0_20
Host: test:6580
Connection: keep-alive
Content-Length: 1107

In other posts it was suggested to turn off keep-alive by using the

http.keepAlive=false

system property, I tried that and the headers changed to

POST /emailauthentication/ HTTP/1.1
Accept: application/xml
Content-Type: application/xml
Authorization: OAuth oauth_consumer_key="b465472b-d872-42b9-030e-4e74b9b60e39", oauth_nonce="Eaiezrj6X4Ttt0", oauth_signature="ND9fAdZMqbYPR2j%2FXUCZmI90rSI%3D", oauth_signature_method="HMAC-SHA1", oauth_timestamp="1276526608", oauth_token="", oauth_version="1.0"
User-Agent: Java/1.6.0_20
Host: test:6580
Connection: close
Content-Length: 1107

the Connection header is "close" but I still cannot read the whole response. Any idea what do I do wrong?