I want to know what does file:/// mean while loading a html file from the assets folder in android
Is it an absolute path name which points to the root
The URI "file:///android_asset/" points to YourProject/app/src/main/assets/.
Note: android_asset/ uses the singular (asset) and src/main/assets uses the plural (assets).
Suppose you have a file YourProject/app/src/main/assets/web_thing.html that you would like to display in a WebView. You can refer to it like this:
WebView webViewer = (WebView) findViewById(R.id.webViewer);
webView.loadUrl("file:///android_asset/web_thing.html");
The snippet above could be located in your Activity class, possibly in the onCreate method.
Here is a guide to the overall directory structure of an android project, that helped me figure out this answer.