Prior to this commit, there was no way to differentiate between an
ApplicationContext "start" and "restart" in terms of events. This was
due to the fact that a ContextStartedEvent was fired for both
AbstractApplicationContext.start() and
AbstractApplicationContext.restart().
To assist developers who may wish to differentiate between "start" and
"restart" events, this commit introduces a new ContextRestartedEvent as
a subtype of ContextStartedEvent. In addition,
AbstractApplicationContext.restart() now publishes a
ContextRestartedEvent instead of a ContextStartedEvent.
By making ContextRestartedEvent a subtype of ContextStartedEvent,
applications can still expect ContextStoppedEvent/ContextStartedEvent
event pairs for consistent lifecycle semantics, and they can optionally
check if the ContextStartedEvent is a ContextRestartedEvent.
Alternatively, applications can explicitly react to a
ContextRestartedEvent.
See gh-35168
See gh-35171
Closes gh-35194
ff1e5a87b3