get system's proxy info

public static void main(String[] args) {
    System.setProperty("java.net.useSystemProxies", "true");
    System.out.println("detecting proxies");
    List l = null;
    try {
        l = ProxySelector.getDefault().select(new URI("http://foo/bar"));
    }
    catch (URISyntaxException e) {
        e.printStackTrace();
    }
    if (l != null) {
        for (Iterator iter = l.iterator(); iter.hasNext();) {
        java.net.Proxy proxy = (java.net.Proxy) iter.next();
        System.out.println("proxy hostname : " + proxy.type());

        InetSocketAddress addr = (InetSocketAddress) proxy.address();

        if (addr == null) {
        System.out.println("No Proxy");
        } else {
        System.out.println("proxy hostname : " + addr.getHostName());
        System.setProperty("http.proxyHost", addr.getHostName());
        System.out.println("proxy port : " + addr.getPort());
        System.setProperty("http.proxyPort", Integer.toString(addr.getPort()));
        }
        }
    }
}