Jetty is described as 'The Jetty Web Server provides a HTTP server and Servlet container capable of serving static and dynamic contend either from a standalone or embedded instantiations' and is an app in the Development category. There are nine alternatives to Jetty for a variety of platforms, including Mac, Windows, Linux, Online / Web-based and Java. The best alternative is Apache Tomcat, which is both free and Open Source. Other great apps like Jetty are Socket.io (Free, Open Source), JBoss (Free, Open Source), ActiveJ (Free, Open Source) and simperium (Freemium).
Apache Tomcat is an open source software implementation of the Java Servlet and JavaServer Pages technologies. Apache Tomcat powers numerous large-scale, mission-critical web applications across a diverse range of industries and organizations.
JBoss is Red Hats Java EE 5-compliant (soon Java EE 6-compliant) application server. It is, as with Red Hat itself, dual-licensed either as open source (community edition) or commercially (enterprise edition).
Alternative Java platform built from the ground up. It is minimalistic, boilerplate-free, and lightning-fast. ActiveJ has minimum third-party dependencies, yet features a full stack of technologies with an async programming model and powerful DI.
Simperium is a service for developers to move data everywhere it's needed, instantly and automatically. Use a Simperium library and write a few lines of code. Simperium can then move any JSON data across multiple versions of your app and your backend services.