Are WebViewClient and WebChromeClient mutually exclusive?

From this great explanation about the differences between WebViewClient and WebChromeClient it seems that if you use one, you shouldn't be using the other (for the same WebView object).

Is my understanding correct?

If not, when would one use both WebViewClient and WebChromeClient for the same WebView object?

Is there an example of a situation where only use both WebViewClient and WebChromeClient for the same WebView object would accomplish a certain goal?

You certainly can use both, they just have different functions. Setting your own custom WebViewClient lets you handle onPageFinished, shouldOverrideUrlLoading, etc., WebChromeClient lets you handle Javascript's alert() and other functions.

Just make your own class, for example:

public class MyWebChromeClient extends WebChromeClient {
    //Handle javascript alerts:
    @Override
public boolean onJsAlert(WebView view, String url, String message, final android.webkit.JsResult result)  
{
  Log.d("alert", message);
  Toast.makeText(context, message, 3000).show();
  result.confirm();
  return true;
};
...

and / or

public class MyWebViewClient extends WebViewClient {
@Override
    //Run script on every page, similar to Greasemonkey:
public void onPageFinished(WebView view, String url) {
        view.loadUrl("javascript:alert('hi')");
    }
...

Just override the functions described in the documentation, then set your client in onCreate with:

webview.setWebViewClient(new MyWebViewClient());
webview.setWebChromeClient(new MyWebChromeClient());