EDIFACT-to-Java Compiler for Smooks v2
Is this correct?
Yes.
Or should I use the XML Schema Compiler (XJC) to generate Java classes and then either map them directly in Smooks, or do a two-step transformation EDIFACT -> (Smooks v2) -> XML -> (JAXB) -> Java?
That's the recommended approach as discussed in the Smooks user forum. The Java bindings for many of the EDIFACT versions have already been generated ahead of time and can be pulled down from the public Maven repository as shown in one of the Smooks examples.