There was a period of time, in mid-late 2010s, when I was hopelessly looking for a web-based IDE that supported programming in Java. There was cloud9 for web programming, but it didn't have Java support. There was Eclipse Che and Theia which were apparently related in some way, but I could never figure out how exactly. They however (Che at least), were painful to install and more importantly required Docker to work, and docker required minimum Linux kernel version 3, while the cheap VPS providers I could afford supported this OpenVZ thing with a patched 2.6.whatever kernel version.... Poooff!
Fast forward to 2022: I finally found VS Code Server by Coder.com, a nice, well-documented project with support for Java and many more languages, and that without docker. OpenVZ has moved beyond obsolete kernel versions, and most VPS providers offer KVM machines with decent prices anyway. Happy seeing this progress :)
By the way, I still don't know how are Che and Theia (and Eclipse, and VSCode it seems) are related to each other.