2) should be the most usually expected result since it occurs when there is no socket connection failures/exceptions; especially when both Client/Server are local, there'd least likely be any issues. 1) appears when connection is slow/delayed; it'll also appear if you switch the setup of delay in the servlets. 3) or 4) occurs when there is a connection failure causing exception.

This scenario would have been more distinctive if we had connected to remote URL/servlets.