URLConnection doesn't use proxy settings

Question

I have a problem with HttpsURLConnection - proxy is not used.
Here is the code:

//proxy
String type = "https";
System.getProperties().put(type + ".proxyHost", host);
System.getProperties().put(type + ".proxyPort", port);
System.getProperties().put(type + ".proxyUser", username);
System.getProperties().put(type + ".proxyPassword", password);

/*some SSL stuff*/

//connection
URL url = new URL(url0);
URLConnection urlConnection = url.openConnection();
urlConnection.setUseCaches(false);
urlConnection.setDoInput(true);
urlConnection.setDoOutput(false);           
urlConnection.setRequestProperty("Connection", "Keep-Alive");   

HttpsURLConnection httpConn = (HttpsURLConnection)urlConnection;
httpConn.setInstanceFollowRedirects(true);
httpConn.setRequestProperty("Proxy-Authorization", "Basic " + Base64Converter.encode(username + ":" + password));
httpConn.connect();

All proxy settings are ignored by the connection and httpConn.usingProxy() is false.
I also tried to pass Proxy instance to url.openConnection() and setting proxy login/password to default Authenticator. The connection used proxy in that case, but I got 407, so it seems that Authenticator doesn't work correctly for me.

Answer 1

System.getProperties().put(type + ".proxyUser", username);
System.getProperties().put(type + ".proxyPassword", password);

According to the official documentation, the JRE does not recognized either of these. I believe the Apache HTTP Client may do so, but don't quote me.

You need to install a java.net.Authenticator.

Answer 2

From How do I make HttpURLConnection use a proxy?:

Since java 1.5 you can also pass a java.net.Proxy instance to the openConnection() method:

//Proxy instance, proxy ip = 10.0.0.1 with port 8080
Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress("10.0.0.1", 8080));
conn = new URL(urlString).openConnection(proxy);

If your proxy requires authentication it will give you response 407.

In this case you'll need the following code:

Authenticator authenticator = new Authenticator() {

    public PasswordAuthentication getPasswordAuthentication() {
        return (new PasswordAuthentication("user",
                "password".toCharArray()));
    }
};
Authenticator.setDefault(authenticator);