The thread pool does not use executors to create, but is threadpoolexecutor way

The thread pool does not use executors to create, but by Threadpoolexecutor way, so
The way of processing let the students write more clearly the thread pool running rules, to avoid the risk of resource exhaustion.
Description: The disadvantages of the thread pool object returned by executors are as follows:
1) Fixedthreadpool and Singlethreadpool:
The allowable request queue Length is integer.max_value, which may accumulate a large number of requests, resulting in OOM.
2) Cachedthreadpool and Scheduledthreadpool:
The number of created threads allowed is integer.max_value, and a large number of threads may be created, resulting in OOM.

The thread pool does not use executors to create, but is threadpoolexecutor way