Why is it that sometimes, closing an application on a phone decreases available RAM instead of increasing it?

Question

Why is it that sometimes, closing an application on a phone decreases available RAM instead of increasing it?

In: 2

Answer 1

I would imagine the app has memory allocated to it in order to work, the operating system then allocates additional space to handle shut down and system saves.

In programming there is a concept called garbage collection where memory that is no longer used is freed up. Most modern coders do not trigger garbage collection on closedown and rely on the operating system to do it, hence you will wait a while for your free memory to go back to normal.

Starting a new app will trigger garbage collection by the operating system so the memory is available immediately anyway.

This is quite simplified.