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

Apache Tomcat version 7.0 implements the Servlet 3.0, JavaServer Pages 2.2,
EL 2.2 and WebSocket 1.1 specifications from the Java Community Process, and
includes many additional features that make it a useful platform for developing
and deploying web applications and web services.

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