that sentence is deceptive. what I means is if there were more servlet/filter/listener using the same singleton...
anyway the loading of the Singleton class happens at the first call in whatever servlet/filter/listener call it.
the unloading of the Singleton class happens at container reloading, and it is becouse the servlet/filter/listener uses it and remains in vm memory until the container restart?
So different thread always refers to the same singleton instance. Could you confirm?