whatever I set the size of pool, the run results seems to not exceed the pool size.For example:
BlockingQueue<Runnable> queue = new LinkedBlockingQueue<>();
ThreadPoolExecutor executor = new ThreadPoolExecutor(8, 15, 1, TimeUnit.DAYS, queue);
executor.execute(new Runnable() {
public void run() {
}
});
when I set 8, the first 8 results will synchronize. But the following only run one by one.
what's wrong and how to fix?
Read the javadoc.
It says:
Queuing
Any BlockingQueue may be used to transfer and hold submitted tasks. The use of this queue interacts with pool sizing:
If fewer than corePoolSize threads are running, the Executor always prefers adding a new thread rather than queuing. If corePoolSize or more threads are running, the Executor always prefers queuing a request rather than adding a new thread. If a request cannot be queued, a new thread is created unless this would exceed maximumPoolSize, in which case, the task will be rejected.
[...]
Unbounded queues. Using an unbounded queue (for example a LinkedBlockingQueue without a predefined capacity) will cause new tasks to wait in the queue when all corePoolSize threads are busy. Thus, no more than corePoolSize threads will ever be created.
