As evident from the TechEmpower Benchmarks, Java is significantly (often orders of magnitude) faster than other, more developer-friendly web frameworks like Django, Rails, or node.js. This means that you disadvantage yourself by creating web startups using these technologies, as scaling becomes a problem quite quickly, and scaling is not an easy problem to solve.

Sparkler is an attempt to bring developer-friendliness to Java web development by using Rails/Sinatra-style Java libraries/frameworks together with Xtend to provide syntactic sugar and other fun language features (like extension methods and lambdas). The result should be the best of both worlds: incredible performance with a developer-friendly framework. The idea is that Sparkler will be fun enough for use in hackathons, as a web startup prototyping tool, and a quick way to get RESTful JSON backends up.

via tobykurien/Sparkler.