how to call destroy() method ?

[sameera liyanage]

how the container identify which servlet instance to call destroy() method ?

[Anirvan Majumdar]

The container doesn't select any particular servlet to call the destroy() method on. It will call the destroy() method on all live instances of servlets that are present.

[Nishan Patel]

Finally, when the servlet is about to be removed from memory, the container calls its destroy() method.
and that is servlet one last chance to clean up resources.