Forge version: forge-1.15.2-32.2.0
Botania version: Botania-r1.15-386

Steps to reproduce: Install Botania, Curios-FORGE-1.15.2-2.0.2.4.jar and Patchouli-1.15.2-1.2-34.jar on a dedicated server, join it and try to equip the Flügel Tiara.

What I expected to happen: Be able to equip the Flügel Tiara without being kicked with a "Internal Server Error" message.

What happened instead: The server keeps running but I can't join it anymore while the Flügel Tiara is equiped.

logs : https://pastebin.com/T5VZ3yh8

what java version are you running on both sides?

Server :
openjdk version "11.0.7" 2020-04-14
OpenJDK Runtime Environment (build 11.0.7+10-post-Debian-3deb10u1)
OpenJDK 64-Bit Server VM (build 11.0.7+10-post-Debian-3deb10u1, mixed mode, sharing)

Running on Debian 10

Client : Version 8 update 241 (build 1.8.0_241-b07)
(Seems like there is a new update of java, installing the new one right now on the client site ...)

Same Issue with the latest java build on client side (build 1.8.0_251-b08)

Fixed the issue by installing OpenJDK 8, thanks for asking what version of java i was running, made me fix the issue !

the issue was that code uses a standard library that got moved in java 11. I just pushed a fix that reimplements the logic without using that library, so the next version you should be able to go back to java 11