sometimes I use a pattern which is very similar to the singleton pattern: There is one default instance which and a static get method to aces it.

But you may create other instances and pass it as optional parameter and if you want to and you can even replace the default instance with a instance from a child class.

So it is NO SINGLETON at all but it is used like one singleton in most cases.

Anyone got an idea who to call something like this ?

Maybe half*** singleton? domiton?