• A much bigger Java runtime, tested against the real JDK: lambdas, streams, List.of and Map.of, your own exception classes, int overflow, compareTo, printf and regular expressions all behave like Java • Compile errors match javac: an ArrayList of int, multiplying a String, or an unhandled checked exception is caught before the program runs, with a hint on how to fix it • When a program crashes, the output it printed first stays on screen, followed by Java’s own error message • Code in Check Your Understanding questions now appears as its own formatted code block • Corrected example output in the double and casting lessons (a double prints as 13.0, not 13) and the String comparison example in Objects and References

• Java practice behaves like a real JVM: Scanner waits for input, number parsing follows Java's rules exactly, and more char and Character methods match the JDK. • Practice problems show exactly where your output differs from the expected output. • Undo and redo in the code editor always undo your own edits.

Fixes and polish: • The "Watch on csplusplus.com" link at the end of each lesson pointed to a page that no longer existed on our site. It now opens the matching lesson page. • Layout fixes so every panel and line of text fits the screen on all iPhone and iPad sizes.