This document discusses the JVM ecosystem and languages. It outlines the rise of modern programming paradigms like dynamic and functional programming. It then discusses core JVM concepts like pure functions, curried functions, and tail recursion. The document profiles popular JVM languages like Groovy, Scala, and Clojee. It explores why JVM languages are growing in popularity and examples of polyglot programming on the JVM. Real-life architectures at companies like LinkedIn and Twitter are presented. Finally, it outlines the roadmap for future JVM versions like JDK 7-9 and concludes that the JVM will continue being successful.