The effective level seems to be the minimum of the handler and logger levels.

So, its possible by setting the handler's level to FINEST, to allow all messages and then restrict the level on the loggers as needed. As an example, to set only MyClass's level to FINEST, use :

.level= INFO # all loggers

java.util.logging.ConsoleHandler.level = FINEST # allow all

com.test.MyClass.level = FINEST # specific logger