If I open the resultset over large data and start calling the resultSet.next(), sooner or later the thread becomes stuck in native SocketInputStream.socketRead0 method.
Firebird is running on one virtual machine and java application that reads the data is running on the other virtual machine. Both machines are Windows Server 2012 R2, but I think the bug also appears on another system. More detailed description I wrote here: https://stackoverflow.com/questions/58872811/jaybird-socketinputstream-socketread0-thread-blocking
I already have test machines on which the error can be simulated. (@Mark, please send me your private mail address and I will send you the access on these test machines)
Thank you for solving.