Java connection failure using web proxy using Apache HttpClient

I have a desktop client that sends data to a web server and I cannot go through a proxy server.

Update : I get an HTTP 407 error when trying to communicate through a proxy.

When downloading information from my web server, everything is in order. When the user configures the proxy server (using the dialog box I wrote), the download works fine. But loading data using org.apache.http.client.HttpClient does not work.

I am setting up a proxy server with code like this after collecting information from JDialog.

        System.setProperty("http.proxyHost", proxyHost);
        System.setProperty("http.proxyPort", "" + portNumber);

Now that we have done this, simple downloads work fine. For example, I have code that reads some XML data from my web server (see below). On the client’s network, an error in my catch block was displayed before the proxy server settings were configured, and then everything worked fine when the correct proxy was installed.

/**
 * Loads a collection of exams from the web site. The URL is determined by
 * configuration or registration since it is State specific.
 */
public static int importExamsWS(StringBuilder msg) {
    try {
        java.net.URL onlineExams = new URL(examURL);
        //Parse the XML data from InputStream and store it.
        return importExams(onlineExams.openStream(), msg);

    } 
    catch (java.net.UnknownHostException noDNS) {
        showError(noDNS, "Unable to connect to proctinator.com to download the exam file.\n"
                + "There is probably a problem with your Internet proxy settings.");
    }
    catch (MalformedURLException | IOException duh) {
        showFileError(duh);
    }
    return 0;
}

However, when I try to transfer data to a web server, it looks like proxy settings are ignored and an IOException is thrown. Namely:

org.apache.http.conn.HttpHostConnectException: Connection to http://proctinator.com:8080 refused

Now I know that port 8080 is not blocked by the client’s web filter, because we tested it in a web browser.

Here is my code for checking the registration ID entered by the user:   Update: now I also install the proxy server in this method.

//Registered is just an enum with ACTIVE, INACTIVE, NOTFOUND, ERROR
public static Registered checkRegistration(int id) throws IOException {    
    httpclient = new DefaultHttpClient();
    Config pref = Config.getConfig(); //stores user-entered proxy settings.
    HttpHost proxy = new HttpHost(pref.getProxyServer(), pref.getProxyPort());
    httpclient.getParams().setParameter(ConnRoutePNames.DEFAULT_PROXY, proxy);
    URIBuilder builder = new URIBuilder();
    String path = "/Proctorest/rsc/register/" + id;
    try {
        builder.setScheme("http").setHost(server).setPort(8080).setPath(path);
        URI uri = builder.build();
        System.out.println("Connecting to " + uri.toString());
        HttpGet httpget = new HttpGet(uri);
        HttpResponse response = httpclient.execute(httpget);
        System.out.println(response.getStatusLine().toString());
        if(response.getStatusLine().getStatusCode()==200) {
            String msg = EntityUtils.toString(response.getEntity());
            GUI.globalLog.log(Level.INFO, "Server response to checkRegistration(" + id + "): " + msg);
            return Registered.stringToRegistered(msg);
        }
        else {
            GUI.globalLog.log(Level.INFO, "Server response status code to checkRegistration: " + 
                    response.getStatusLine().getStatusCode());
            return Registered.ERROR;
        }
    }
    catch(java.net.URISyntaxException bad) {
        System.out.println("URI construction error: " + bad.toString());
        return Registered.ERROR;
    }
}

, -, docs SystemDefaultHttpClient , http.proxyHost http.proxyPort. , , . , , :

checkRegistration INFO: Server response status code to checkRegistration: 407 

?