Java <name> has joined your team!

[CrystalDrop]

This is a pretty good idea. To help with the spam concern perhaps you can simply toggle on and off the notification as you please in settings. +1

 

[OnlyTijmen]

I like the idea, but I think just as @Milhato already said, there should be a way to turn it off, so your chat wont be flooding with messages, especially on the teams of 10 maps.