public static void main(String args[]) throws Exception {
    debug(DebugParameter.custom().setProxyHost("http://1.2.3.4:8080").build());
}

If you set a specific proxy host via above code then these code will be executed before starting the Debug App.

System.setProperty("http.proxyHost", "1.2.3.4");
System.setProperty("http.proxyPort", "8080");

Attention: Please do not set proxy host and port directly via System.setProperty (..). It will affects all other plugins and Actlist application.