Java 8 is released and you might have played around with the new lambda features. Regrettably, when you return to your day job you find yourself stuck with an older version of Java. You know from experience that it will take a while before you can enjoy your new powers in a production environment. Fortunately, it is actually possible to leverage some of the functional-style techniques even in older Java versions. This means that you can program in a functional style, even if your organization has not updated to Java 8.