Java is an open source programming language specifically designed to create universal applications that run on any operating system, open source or otherwise. It achieves this apparent magic by using a runtime specific to each OS. This runtime interprets the Java code so that the application runs as expected. It's an effective method that enables programmers to write their code once but deliver it to all computers that run Java (Linux, BSD, Windows, and Mac, to name the common ones).
No matter how often you write code, though, there's bound to be something you don't use often enough to type without a reference. Maybe you can't remember whether to include or import or how to parse incoming arguments. There are a few ways to bridge such a gap: you can use a robust IDE and let it autocomplete the obvious parts, or you can keep a cheat sheet handy to get a little control over all that dizzying syntax.
While Java's too big to be contained on a two-page cheat sheet, whether you're new to programming or you only dip into Java every once and a while, this cheat sheet gets you up and running. Perhaps most importantly, it provides you with added context for what you're trying to remember. You don't have to blindly choose between prompts from your IDE for a private or public method; you can get clarity instead. And let our cheat sheet inspire you to create your own as you go. The next time you stumble over syntax that's not covered on this cheat sheet, open up a notebook or a text file and jot down the solution. When you get enough good ones, let us know what they are, and who knows? Maybe a sequel can be arranged!