It's relatively easy to control MQTT equipment from Home Assistant. To make Home Assistant-controlled devices available over MQTT requires a bit of work, especially to make a generic configuration that is easy to add more lights to in the future.
Apache Tomcat is a Java Web Server that runs Web Application Resource (WAR) files, a common way to run Java applications. A common tuning parameter is the amount of heap space (memory) allocated to the Java process that runs Tomcat. How to set it, and to monitor and change it on Windows when Tomcat runs as a service is not obvious.