It also makes it simpler for humans looking at the source code, to find where things are defined. Nowadays, most of us would use a good
IDE and this becomes a non-issue. But there were no such nice IDEs for Java in the early days. And even now, sometimes you're looking at code on a server where you don't have an IDE installed. It's nice to just know where the code should be, rather than having to load the code on a different machine before you look at it.