About Question enthuware.oce-jpad.v6.2.525 :

[ETS User]

The note says:

Note that Collections of non-serializable types be used as mapping type. However, since the question only asks about the type of the persistent attribute, this option is valid because the option is does not have any generic type information.

I guess, it should be:
Note that Collections of non-serializable types must not be used as mapping type. However, since the question only asks about the type of the persistent attribute, this option is valid because the option is does not have any generic type information.

[admin]

You are right. This has now been fixed.
thank you for your feedback!