// Java 17 // makes IMMUTABLE objects record Book(String title, String author, int numPages, boolean isCopyrighted) {} /* This makes a class with four fields. * It auto-makes: * - a constructor (takes four args, fills them directly into the fields); * - a toString * - a .equals (two Books are .equals if, and only if, all their fields are .equals) * - hashcode() * - getters: `title()`, `author()`, etc. * - NO setters -- immutable fields. */