Java try catch finally无限递归问题

Question

执行如下代码环，其递归循环次数将达到3^N次(N为最大栈深)为天文数字因此几乎无限循环

    public static void foo() {
        try {
            System.out.println("try");
            foo();
        } catch (Throwable e) {
            System.out.println("catch");
            foo();
        } finally {
            System.out.println("finally");
            foo();
        }
    }

上面代码控制台打印内容如下,我好奇的为什么没有输出“catch”，将上述的catch (Throwable e) 换成catch (StackOverflowError e)后正常输出“catch”

···
try
try
try
try
try
try
fifinallyfinallyfinally
tryfinallyfinally
try
tryfinallyfinally
tryfinallyfinally
try
try
···

我尝试去统计try/catch/finally块的执行次数，编写如下代码，创建一个线程每隔3秒钟输出统计结果

    static Counter counter = new Counter();
    public static void main(String[] args) {
        new Thread(() -> {
            try {
                for (; ; ) {
                    TimeUnit.SECONDS.sleep(3);
                    System.out.println(counter);
                }
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
        }).start();
        foo();
    }

    static void foo() {
        try {
            counter.t++;
            System.out.println("try");
            foo();
        } catch (Throwable e) {
            counter.c++;
            System.out.println("catch");
            foo();
        } finally {
            counter.f++;
            System.out.println("finally");
            foo();
        }
    }
    static class Counter {
        int t, c, f;

        @Override
        public String toString() {
            return "Counter{" +
                    "t=" + t +
                    ", c=" + c +
                    ", f=" + f +
                    '}';
        }
    }

结果控制台输出如下结果，可以看到try、catch、finally块的执行次数基本相同(try块初始化递归时多了一个最大栈深的次数)

try
try
trycatcatchfinallycatchfinallycatchfinally
trycatchfinally
trycatchfinallycatch
try
···
···
trycatchfinallyCounter{t=17028, c=10621, f=10615}

可是当我将创建输出统计结果的线程的代码注释掉后“catch”又不输出了,甚至当我仅仅创建该线程不去start()时却可以输出“catch”，有谁知道这个“catch”什么情况下输出吗？

Answer 1

你这里好像处了异常也不会进入finally吧, 因为打印''catch''后又进入递归了吧,
然后也不知道你想要干什么, 纯粹闲的慌

    public static void foo() {
        try {
            System.out.println("try");
            foo();
        } catch (Throwable e) {
            System.out.println("catch");
            foo();
        } finally {
            System.out.println("finally");
            foo();
        }
    }