我的LinkedBlockingQueue实现是否需要同步？

Question

To begin with, I have used search and found n topics related to this question. Unfortunately, they didin't help me, so it'll be n++ topics :)

Situation: I will have few working threads (the same class, just many dublicates) (let's call them WT) and one result writing thread (RT).

WT will add objects to the Queue, and RT will take them. Since there will be many WT won't there be any memory problems(independant from the max queue size)? Will those operations wait for each other to be completed?

Moreover, as I understand, BlockingQueue is quite slow, so maybe I should leave it and use normal Queue while in synchronized blocks? Or should I consider my self by using SynchronizedQueue?

Answer 1

LinkedBlockingQueue is designed to handle multiple threads writing to the same queue. From the documentation :

BlockingQueue implementations are thread-safe. All queuing methods achieve their effects atomically using internal locks or other forms of concurrency control. However, the bulk Collection operations addAll , containsAll , retainAll and removeAll are not necessarily performed atomically unless specified otherwise in an implementation.

Therefore, you are quite safe (unless you expect the bulk operations to be atomic).

Of course, if thread A and thread B are writing to the same queue, the order of A's items relative to B's items will be indeterminate unless you synchronize A and B.

As to the choice of queue implementation, go with the simplest that does the job, and then profile. This will give you accurate data on where the bottlenecks are so you won't have to guess.