Um, a slight adjustment: it disappears when it is cleared from memory. Which is important if you think you are instantiating a new object from a "fresh" class, but you are really using the class in memory.

...snip
>Bottom line, if you create a class in code, it is created whenevery you run the code, but is does not become part of a class library (.vcx table), and ceases to exist when you exit from your code.