W3School TIY Editor

public class Main { final int x = 10; final double PI = 3.14; public static void main(String[] args) { Main myObj = new Main(); myObj.x = 50; // 将产生错误：无法为 final 变量赋值 myObj.PI = 25; // 将产生错误：无法为 final 变量赋值 System.out.println(myObj.x); } }