Question

I am exercising my multi-threading skills in java. Below is a piece of code that is supposed to remove a folder and make sure that:

if (freshDB) {
    LOG.warn("Refreshing the database!");
    ExecutorService executorService = Executors.newSingleThreadExecutor();
    final Future<Boolean> result = executorService.submit(new Callable<Boolean>() {
        public Boolean call() {
            return FileHandler.removeFolder(dbLocation);
        }
    });

    do {
        // makes sure the folder is removed
    }
    while (result.get() == false);
}

Is this the right way to do it? if not why? please elaborate.

Answer 1

No, it’s not.

First of all, the loop at the end doesn’t make much sense. result.get() will always return the same value: the submitted task is excuted only once, and result.get() will return the result of this single execution.

And anyway, what’s the point of starting a new thread if the initial thread immediately stops, waiting for the started thread to be finished? Doing everything in the initial thread would be much simpler, and more efficient.