Java and JavaScript are both popular programming languages but have key differences. Java is a compiled, class-based language that runs on the Java Virtual Machine (JVM) and is well-suited for desktop applications. JavaScript is an interpreted scripting language best known for powering interactivity on web pages through browsers without plugins. Some key differences are that Java is statically typed while JavaScript is dynamically typed, Java code must be compiled while JavaScript code can run immediately, and Java is better for desktop apps while JavaScript excels at client-side web development. In the end, the document recommends Java for desktop apps and JavaScript for web design and development work.