is java necessary for mac

If you don't run any Java apps you don't need it.

Depends where you get an update, if it pops up as you're browsing the Internet then it's a scam & malware...

https://malwaretips.com/blogs/remove-fake-flash-player-update/

aw19 wrote:

Should I update Java whenever I get an update.

So, in that case—yes ;)

Amen

If you do anything requiring Java then you need it.