What does it download from its Maven repository?

Question

Maven

I don’t understand one thing, why does he download something when building a project?
Though probably at first it is necessary to understand that it downloads.
As I understand it, the necessary ones for the project to be built? Why do you need a JDK then?
But the most annoying thing is that rebuilding the same project without changes
Means compile - clean - compile, it shakes constantly. Doesn't he have internal storage for already downloaded stuff?

Answer 1

And what is 1.0-SNAPSHOT?
Is this the version of the project, is it possible to change this value?
Actually, it would be nice to get some kind of link :)
I would be sincerely grateful to everyone

Answer 2

For the first time, Maven downloads its own libs needed to build the project.
What does it download every time - show your pom.xml, at least the dependencies and build / plugins sections, you can make an assumption.
Here are a couple of good videos to understand how Maven works in an hour and a half:
www.youtube.com/watch?v=IAbZVA4tK6M
www.youtube.com/watch?v=Grl1GhklwDQ