Collectible Card Game Headquarters

Hello,
Xmage can't download java for some reason (the link it downloads it from gives a 404 error). I'd like to do it manually, what's the procedure please?

To clarify,
I have reinstalled the launcher and tried to download the JSE directly from oracle but then I don't know what to do. The Java version on my computer is up to date. I use Windows 10 64-bit.

Just marking this issue as closed. Oracle fixed their thing and it's working now