Palla, Groovy is a dynamic language on top of the JVM. It preserves the Java semantics, most of Java syntax is Groovy syntax as well. That gives you a flat learning curve if you are already familiar with Java. You can get started quickly in that case and start to take advantage of concepts in Groovy like Closures, builders, and metaprogramming. How long does it take? It will take shorter if you practice by writing code and playing with it than only reading a book. Read a little and then write code example and take it from there and modify. Build a little application, a pet project. This is an advice I always give no matter what language you learn. I say write little lousy apps and break them, make them work again, and you will come out way ahead learning the stuff quickly than any other means in my opinion.