Currently there is no possibility to give an option to the 'field set/list' commands to declare that the mappedBy field in the child side, which holds the reference to the parent (in a ONE_TO_MANY relation), to be notnull or not. At the moment the generated code ALWAYS is without @NotNull for the mappedBy field on the child side!
We would like to define an ONE_TO_MANY relation, where the child have a foreign key set (often needed in real life). In previous spring roo versions this was possible via the 'field reference' command. But since this command is only for ONE_TO_ONE relations (I think this was introduced by
ROO-3793) there is no way to do that for now.