线程池,submit,结果是String类型为啥返回空?
输出:
ExecutorService线程[1]
ExecutorService线程[2]
Tue Nov 06 16:39:29 CST 2018
Tue Nov 06 16:39:31 CST 2018
Tue Nov 06 16:39:31 CST 2018
ExecutorService线程[2]
Tue Nov 06 16:39:29 CST 2018
Tue Nov 06 16:39:31 CST 2018
Tue Nov 06 16:39:31 CST 2018
而传入一个单独定义的Class后,就能返回正确结果了,为啥呢?