Answer 1

How many times are you going to ask the same question over and over again?
You can literally do it with ANY programming language. It is a personal preference and subject to the expertise of the developer and the details of the particular project, which technology is more suited for any specific programming task. You can do fullstack development, including backend, with pure javascript too. If someone is an expert in that but has no clue about Java or Python, they will pick JavaScript first.