Java program, I need a socket for other machine orders, wait until the command screen immediately hit log,
Usually no problem, other machines using a socket connection, can see the screen printed,
But sometimes, it is stuck in there, there is no output, however, as long as I press a button and the screen printed immediately,
This is how did that happen? My program doesn't have anything to do with manual input,

Later, I found that I in bat program, wait a few seconds to start another application, occasionally found that the timeout also stuck silk, time has passed for a long time, obviously it is not moving down,

I don't understand, this is how did that happen?
The bug is Windows?