Hi,
The easiest solution may be to store a list as a string with comma separated values. When you need to display it in UI, convert this string to a collection of enums and set the collection to the UI component. When you need to save it, convert a Collection<MyEnum> into a string with comma-separated enum ids.
Also, you may define a JPA AttributeConverter, similar to the one, described in this topic. Your converter will convert a List<MyEnum> into a String. In this case your entity will have a field of List<MyEnum> type, and a conversion to a string with comma-separated values will be done inside the converter.