Application/object halts for (exactly) 1 hour

Question

One processing object of my application occasionally halts for exactly 1 hour (60 minutes) and i wonder what the reason can be. The application itself is multithreaded and can run multiple threads. The application itself doesn't halt (log entries) but one thread that first downloads data via HTTP to a file and then processes the file sometimes halts and continues after 60 minutes. For the download part, i set a timeout of 10 minutes (not 60 minutes) and this timeout also is just for the download part. After downloading, the file processing starts that reads from the file and performs some database (JDBC) statements (SELLECT, UPDATE, INSERT). The application itself shows the running time of the thread. When the thread processing continues, i see in the database that there is a jump of exactly 60 minutes between the last and the subsequent access before/after the halt. There is no timeout oder exception or anything else. It just sleeps for 1 hour and then continues.
Can one reason be some MS SQL issue that just makes one connection sleep? Or any other possibility?

Answer 1

and of course you don't have these Sleeps in a loop that mysteriously executes exactly (60 minutes / sleep time) times ?
just add more checking around the code that connects to db:System.out.println("Connecting at <time>");
// ins, sel, upd
System.out.println("Done at <time>, took <timediff>"); and so on... it is mysterious and indicative of an error on your part that it takes exactly one hour.
unless there is a strange situation like the server where the db lives resets it self at x'olock and takes 1 hour to get back up... etc.