I wanted to ask if I need a Live Gold membership on the Xbox One to play Minecraft with friends on a server I set up myself?

If that changes my friends are playing on PC

If they are playing the Java Edition you can't play with them.

This is only possible with the Bedrock version, and for that you need Live, yes.

If you want to play online on Xbox, you need Xbox live Gold.

Except for free to play titles.

OK thanks

OK, so with Java Edition it doesn't work at all, right?

No.