I have re-tested HHH-10857 Open with Hibernate 5.4.15:

• For “simple” Embeddables (directly used in the Entity as @Embedded), @Convert annotation works.

• For Embeddables in ElementCollections, @Convert annotation also works now. So, the original issue HHH-10857 Open seems to be fixed.

• However, in the following situation, @Convert is still ignored:

• I have an Element Collection of an Embeddable OuterEmbeddable.

• “OuterEmbeddable“ contains another Embeddable called InnerEmeddable

• Within InnerEmeddable I use @Convert on basic fields. But it is ignored.

My current workaround is to use @Convert one level higher:

@Embeddable
class OuterEmbeddable{
  @Convert(converter = MyConverter.class, attributeName = "theFieldToConvert")
  InnerEmeddable theInnerEmbeddable
}