EDIT

add class information to exception

add additional debugging in AbstractPersistentCollection

ref #9204 some more documentation on how to handle AbstractPersistentCollection

ref #9204 uncritical minor final changes to AbstractPersistentCollection

ref #9204 final changes to AbstractPersistentCollection (also seem to be not really critical)

ref #9204 further uncritical updates to AbstractPersistentCollection

ref #9204 probably uncritical updates to AbstractPersistentCollection

ref #9204 further uncritical updates to AbstractPersistentCollection

ref #9204 change logger in AbstractPersistentCollection

ref #9204 uncritical updates to AbstractPersistentCollection