一只后端汪

直接看代码

join

public final V join() {
    int s;
    if ((s = doJoin() & DONE_MASK) != NORMAL)
        // 如果没有正常完成去处理异常
        reportException(s);
    return getRawResult();
}

doJoin

private int doJoin() {
    int s; Thread t; ForkJoinWorkerThread wt; ForkJoinPool.WorkQueue w;
    // status<0表示任务已经执行完毕
    return (s = status) < 0 ? s :
    ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) ?
        (w = (wt = (ForkJoinWorkerThread)t).workQueue).
        tryUnpush(this) && (s = doExec()) < 0 ? s :
    wt.pool.awaitJoin(w, this, 0L) :
    externalAwaitDone();
}