Apache Tomcat is a web server written in 100% Pure Java.

Apache Tomcat 10.1.x is the current focus of development. It builds on
Tomcat 10.0.x and implements the Servlet 6.0, JSP TBD, EL TBD, WebSocket TBD
and Authentication TBD specifications (the versions required by Jakarta EE 10
platform).

WWW: https://tomcat.apache.org/