final

1. 被final关键字修饰的类不能被继承 final class Father{ } public class Son extends Father { }　//Son不能继承Father类 2. final 修饰的方法不能被重写 3.final 修饰的变量叫常量，常量必须初始化，初始化之后值就不能被修改 （1） 对于一个final变量，如果是基本数据类型的变量，则其数值一旦在初始化之后便不能更改；如果是引用类型的变量，则在对其初始化之后便不能再让其指向另一个对象。 　　上面的一段代码中，对变量i和引用型String a的重新赋值都报错了，而b没报错。 （2）引用变量被final修饰之后，虽然不能再指向其他对象，但是它指向的对象的内容是可变的。如下解释 public class Test { public static void main(String[] args) { final MyClass myClass = new MyClass(); System.out.println(++myClass.i); } } class MyClass { public int i = 0; } 来源： https://www.cnblogs.com/Hitleren/p/11528855.html

I am trying to simply time a function by using the Runnable interface to wrap around whichever function I need. private static double time(Runnable runnable) { // returns how long runnable took long startTime = System.nanoTime(); runnable.run(); return (System.nanoTime() - startTime) / 1000000000.0; } then I could simply do the following: double durationOfFunctionA = time(Driver::functionA); // functionA belongs in class Driver however, if I have a function that takes a parameter, it must be modified to: double durationOfFunctionB = time(() -> functionB(someParameter)); The problem I am having