Test system proxy server settings.

ProxyTest.java

import java.util.*;
import java.io.*;
import java.net.*;

public class ProxyTest
{
    public static void main(String[] args) {
        System.setProperty("java.net.useSystemProxies", "true");
        List<Proxy> list = null;
        try
        {
            list = ProxySelector.getDefault().select(new URI("http://google.com"));

            for (Proxy p : list) {
                System.out.println(p.toString());
            }
        }
        catch (final URISyntaxException e)
        {
            e.printStackTrace();
        }
    }
}