Explore the versatility of JVM languages in this live coding session from Devoxx 2017. Discover how to leverage Java 9, Scala 2.12, Groovy 2.4, and ECMAScript 2015 (ES6) to efficiently tackle various programming tasks. Watch as senior consultant Jonatan Kazmierczak demonstrates the calculation of mathematical expressions, processing of text templates, handling collections and maps, and JSON processing using interactive shells, including the newly introduced JShell in JDK 9. Learn how to combine these languages into a powerful "Swiss Army knife" for JVM-based development and integrate it into a sample Java application built with Gradle 3. Gain insights from Kazmierczak's 20 years of Java experience and prepare to optimize your JVM toolbox for enhanced productivity and efficiency in your development projects.