A couple of my friends recently started hosting a minecraft server, after getting tired of how bad Realms was, and that was all good, but I am currently getting internet lag spikes from time to time. At first I thought it happened whenever someone was loading the world, as we had render distance set to 15 chunks, but then I figured out that it happened at random, even when I was alone on the server AND had been standing still for the past 10 minutes. Even after reducing server render distance to 10 chunks, it continues.
The picture below shows what happens, and all of the bandwidth usage is due to "Java(TM) Platform SE binary". This wouldn't be a problem if not for the fact that the internet in this house is a measly 10/1 (but goes up to 12/1.2 or so) shared by 6 students, and these spikes cause me to lag out on occasion.
I can be standing still, AFKing near my mob farm or whatever, and it will suddenly drain a lot of internet. It's important to note that this does not happen on another server I've tried, nor the previous Realm we played on. What's even more curious is that it sends so much data, as if it was a security breach and someone was pulling data from my computer. Usage goes from zero to 100 in a second, and can slowly wane off after a while.
I've downloaded the latest java, and memory is set to 4 GB (same result as default). What is happening?