Java 21

This handbook explains in detail the features of the twenty-first version of the Java language. It guides the reader through all the intricacies of the language, from the absolute basics to advanced constructs. It covers all elements of the language, including those that are only included as a preview and will become a standard part only in a future version. At the same time, it shows how to activate and test these preview constructs.
The explanation is designed so that the book serves as both a textbook and a reference guide. It will therefore be useful for beginners and advanced programmers, who will find explanations for the causes of many problems they encounter daily, along with instructions on how to solve them. It also explains in detail topics that other textbooks omit due to lack of space, thus forcing programmers to sometimes proceed by trial and error.
The described constructs are demonstrated in the JShell environment, which allows for a simple and effective demonstration of the function of most of the topics explained without the unnecessary fluff required when using the classic approach. This allows everyone to easily try out the constructs and possibly experiment with them further, without having to write auxiliary code with test methods and control prints and perform separate compilation. This approach significantly facilitates the use of the handbook in basic programming courses. Detailed explanation of the language's features from the very basics to advanced, not commonly discussed constructs In addition to current constructs, it also explains those that are built-in only as a preview and will become standard only in a future version Uses the built-in JShell REPL environment to demonstrate the explained constructs without unnecessary auxiliary code Shows how to experiment effectively and get immediate answers using the JShell environment Ideal as a textbook and a reference guide