https://stackoverflow.com/questions/20886309
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RussianThe field factors was attempted to be mapped to a field factors of a a new object of type Elementary, but the property here is a List interface for which no concrete type is known.
The mapping of this field works for actual domain model types, but not for hibernate proxies.
Do you initialize factors with an ArrayList? It seems so otherwise the non Envers mapping would not work.
This could have to do with some limitations that dozer has in mapping generic types such as lists, due to the fact that generic information is not available at runtime, so dozer does not known the type of the objects that a list contains, so it tries to infer it from the contents of the source collection.
According to the Dozer documentation:
If a Hint is not specified for the destination field, then the destination Collection will be populated with objects that are the same type as the elements in the src Collection.
So to solve this there are several ways:
1 - Put a dozer hint on the mapping of this property to specify the target type, that way it will not try to infer it:
<field>
<a>factors</a>
<b>factors</b>
<b-hint>your.target.class.Here</b-hint>
</field>
2 - write and apply to this property a Dozer custom converter, where you map this list manually, this would always work (use the custom converter API that is generics based).
3 - Avoid the need for mapping and Dozer altogether, by solving the LazyInitialization at serialization time in another way: ensure the hibernate session is kept open all the way up to the serializing of the request, by using Open Session In View if in a Spring application, or similar if otherwise.
One of these ways should solve it, if still in doubts you can always:
post the dozer mapping and the code for the type of
factors?With the debugger can you put a breakpoint in ConstructionStrategies line 280 to see what is the abstract class or interface that it's trying to instantiate.
