I am using collection-composite-element, having mapping

<set
name="assignedMachineList"
table="employee_machines"
lazy="false"
inverse="true"
cascade="all"
sort="com.mrt.vend.desktop.model.AssignedMachine"
>

<key
column="emd_emp_id"
>
</key>

<composite-element
class="com.mrt.vend.desktop.model.AssignedMachine"
>

Saving object containing above specified sorted set, does not save any changes to any of the elements on the set.

Changes made only to the inverse end of the association are not persisted. You have to manually save()/delete() the set-elements, if the assignedMachineList is modified.
Another alternative ist to declare the other end of the relationship as "inverse".

I can set inverse = false, however this is causing to perform insert without delete, I mean it tries to insert existing rows, it fails on key constraint violation.
On other hand I can not delete these rows upfront because composite-element is not persisted itself. The only way I see it can work is to delete these rows upfront manually.