Hi Dominik,
actually, it's a kind of feature....
Most important is that the values REPOHOST and REPOPORT are set in the configuration of the Jobserver.
You can find its configuration on the config tab of the jobserver in the web GUI.
Most of the time it'll be sufficient to set those two values at GLOBAL level and have them inherited down the tree.
If you have a special network design where the host running the scheduling server has different names or IP addresses depending on the subnet from where you want to access it, you'll have to specify those values at lower level.
If a Jobserver connects, the scheduling server will send it its configuration.
Then, if the Jobserver detects that the REPOHOST and/or REPOPORT values (or any of the other values like USE_SSL, TRUSTSTORE, KEYSTORE and alike) differ from the value it finds in its configuration file, the Jobserver will update its configuration file, disconnect and reconnect.
This comes in very handy if you want to move the scheduling server from one host to another, if you want to enable or disable SSL communication, or if you want to rename the Jobserver (e.g. redesigning the scope tree).
What I find odd is that you say this happens since you've updated Java.
So far I didn't receive any issue reports (well, apart from the garbage collector's configuration).
Hence, please check the config of the Jobserver and correct it if required.
If everything looks OK, we'll have to search deeper for the cause.
Best regards,
Ronald