My girlfriend just bought Minecraft today, and once we installed the Minecraft launcher and tried to launch the Java version, it asked her to make a Minecraft Java username. However, whatever words or letters were entered into the box popped up with the prompt "Username has already been taken", and wouldn't allow for the creation of any username.

We then tried to set it on minecraft.net, logged in with Microsoft account, and tried setting a username there. On here, no matter what was put in, gave "You can't use language that some might find offensive", and also wouldn't allow for the creation of any username.

This makes trying to play the Java version impossible right now.