UrlUtilities problems (and how to solve them)

[BPP4634]

Good afternoon. I've been looking up your code and I think you could make some minor improvements to the UrlUtilities class. First, there is a never-ending recursive method: the buildUrl with 4 parameters, and second, I think you should take into consider changing some hardcoded strings like "https" or "http" into constants, as they are used many times there. I have also attached a file of what the solution could be like.
I know this text doesn't match the issue template, but I don't think I should follow that template for this particular one.

ISSUE FLICKR4JAVA.pdf