Apache HTTP Server - Apache httpd has been the most popular web server on the Internet since April 1996
OpenXava - OpenXava is a Web Java Framework for Rapid Development of Enterprise Applications.
Cherokee - High-performance web server
jHipster - JHipster is a development platform to quickly generate, develop, & deploy modern web applications & microservice architectures.
Caddy - The HTTP/2 Web Server with Automatic HTTPS
Spring Framework - The Spring Framework provides a comprehensive programming and configuration model for modern Java-based enterprise applications - on any kind of deployment platform.