What actually happens when we open a connection to the file while creating a stream object?

Say when I write,

InputStream inStream = new FileInputStream("LOCATION");

So what happens with the new FileInputStream("LOCATION") part?

I read materials on the web stating it opens a connection to this location. So by "opening a connection" should I assume that it's bringing entire data from "LOCATION" into the inStream?

And if it is not bringing the entire data then what it does?