DataKernel is described as 'Java components for building extremely fast and scalable applications with asynchronous I/O' and is an app in the Development category. There are eight alternatives to DataKernel for Mac, Windows, Linux and Online / Web-based. The best alternative is Apache Tomcat, which is both free and Open Source. Other great apps like DataKernel are Jmix (Free, Open Source), Spring (Free, Open Source), Jetty (Free, Open Source) and GWT (Google Web Toolkit) (Free).
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.
Play is a web application framework, written in Scala and Java, which follows the model–view–controller (MVC) architectural pattern. The Play framework makes it easier to build web applications with Java & Scala.
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.