A PDF annotation webapp and Angry Birds both use Java via GWT . Web gaming technologies: Angry Birds’ cross-compiled Java versus native JavaScript Labels: angry birds , dev , gaming , java , webdev After it became clear that Angry Birds was basically a true webapp with only a little Flash to overcome the limitations of web-based audio [1], more information came to light regarding the technology it is based on [2]. Cross-compiled Java Following the naming school of “fun with double-entendres”, the technology is called “ForPlay”. Quoting the website: ForPlay is a cross-platform game abstraction library for writing games that compile to: Desktop Java HTML5 Browsers Android Flash [...] ForPlay is free and open source, and we hope you will make kick ass games with it! That is, you write your game in Java and then can cross-compile it to Desktop Java, a webapp (via Google’s GWT ), Android, or Flash. Quite impressive, even though some platform-specific code is always necessar