Not sure why you see UTC time in the messages. Maybe because of explicit setting it for JVM via user.timezone property. To eliminate the time as a possible reason, make sure Studio, Tomcat and your OS work in the same timezone.
Regarding what can be hot deployed.
- What works:
- XML descriptors and screen controllers (including static methods), located in web and gui modules
- Middleware service implementations, located in core module
- What doesn’t work:
- Any classes of the global module, including middleware service interfaces
- Other UI and middleware classes and beans, including their static methods, hot deployed ONLY IF some class from item 1 has also been changed. The reason for this is that class reloading is started by some signal: for screen controllers it is the screen reopening, for services - Studio generates special trigger file that is recognized by server and used to reload particular service class and all its dependencies.
So in general, while you work with the UI layer code and service implementations, you don’t have to restart the server. However, item 3 may bring some confusion. If you change entities, entity listeners, service interfaces or other classes on middleware or in the global module, you should restart even if you see “Hot deploy” message in Studio log.