首先来看笔者遇到的一道面试题,阅读下面的代码并给出执行结果:
class Singleton {
    private static Singleton singleton = new Singleton();
    public static int counter1;
    public static int counter2 = 0;
    private Singleton() {
        counter1++;
        counter2++;
    }
    public static Singleton getInstance() {
        return singleton;
    }
}
public class TestSingleton {
    public static void main(String[] args) {
        Singleton s ...