Android Webview & Javascript Calls

I have created a Vaadin 7 application that runs on a server, the client gets an Android Webview ‘application’ that uses webview to go the Vaadin application. Within Android application I am using the WebAppInterface that let Vaadin connect with the native android application in order to i.e. get the device S/N, vibrate etc… using this:

mWebView.addJavascriptInterface(new WebAppInterface(this), “Android”);

Which means that when I call from the Vaadin i.e. JavaScript.getCurrent().execute(“Android.vibrate(300)”); the device vibrates.
However, this means that the android native app injects the javascript Android code within the webview, at the PC browser if I go to ‘debug’ mode I get the following error:
Error performing server to client RPC (ReferenceError) : Android is not defined
which makes sense since the javascript Android was never loaded using a browser (i.e. firefox)…

Any way to choke these kind of messages for the specific javascript?? Again, this comes up only if I use the ?debug, otherwise I don’t see any error messages.