Every programming languages has communities built around them.
Its becoming clear Rust solves a lot of C/C++ type problems and the embedded communities are definitely shifting over.
Apache is the primary community for Java, a quick look at their project list shows it's entirely web servers, data engineering and clustered projects for distributed computing.
Personally if you asked me to solve this problem I would use Spring Boot with various Spring libraries for talking to the caddy, user control, etc... Looking at the project, its exactly what they have done