#!java and #!javascript

On the vaadin site there are code segments beginning with #!java or #!javascript. Is the purpose simply to give the reader an idea of the type of file (.java vs. .js) that the code could be expected in?

Or is it a well-known syntax used across industries?

Thanks

It’s primary function is for the page to enable the right type of syntax highlighting for the code snippet, but also to inform the user of what language the code is written in.