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Here we unmarshal the byte stream into a HAPI Message object that is passed to our patient lookup service.

Notice there is a shorthand syntax in Camel for well known data formats that is commonly used.
Then you don't need to create an instance of the HL7DataFormat object:

  from("direct:hl7in").marshal().hl7().to("jms:queue:hl7out");
  from("jms:queue:hl7out").unmarshal().hl7().to("patientLookupService");

The unmarshal operation adds these MSH fields as headers on the Camel message:

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