PKG
ScheduledExecutorService
CPU
ThreadPoolExecutor
任务
ExecutorService
线程池
Future
Readable
任务的两级调度模型
主线程
Callable
FutureTask
线程
get
Runnable
OSKernel
AbstractExectorService
FUtureTask
return
execute
canel
Executor
ScheduledThreadPoolExecutor
RunnableFuture
submit
Executor框架
