FHIR Chat · Java cast error in JAR validator

Stream: implementers

Topic: Java cast error in JAR validator

Morten Ernebjerg (Oct 15 2018 at 12:41):

End of last week, I started seeing the following Java error being thrown by the latest version of the standard JAR validator (https://build.fhir.org/validator.zip) when validating STU3 resources:

Error java.lang.ClassCastException: org.hl7.fhir.r4.model.Parameters cannot be cast to org.hl7.fhir.r4.model.TerminologyCapabilities validating Coding`

For instance, here is the output when running against one of the standard STU3 examples (https://www.hl7.org/fhir/observation-example.xml):

java -jar org.hl7.fhir.validator.jar -version 3.0.1 observation-example.xml
FHIR Validator Build ??
Arguments: -version 3.0.1 observation-example.xml
  .. connect to tx server @ http://tx.fhir.org
  .. definitions from hl7.fhir.core#3.0.1
    (v3.0.1-null)
  .. validate [observation-example.xml]
Terminology server: Check for supported code systems for http://loinc.org
Terminology server: Check for supported code systems for http://loinc.org
Terminology server: Check for supported code systems for http://acme.org/devices/clinical-codes
*FAILURE* validating observation-example.xml:  error:4 warn:0 info:0
  Error @ Observation.code.coding[1] (line 21, col11) : Error java.lang.ClassCastException: org.hl7.fhir.r4.model.Parameters cannot be cast to org.hl7.fhir.r4.model.TerminologyCapabilities validating Coding
  Error @ Observation.code.coding[2] (line 26, col11) : Error java.lang.ClassCastException: org.hl7.fhir.r4.model.Parameters cannot be cast to org.hl7.fhir.r4.model.TerminologyCapabilities validating Coding
  Error @ Observation.code.coding[3] (line 32, col11) : Code system validation not supported in R2
  Error @ Observation.code.coding[4] (line 38, col11) : Error java.lang.ClassCastException: org.hl7.fhir.r4.model.Parameters cannot be cast to org.hl7.fhir.r4.model.TerminologyCapabilities validating Coding

Has anyone seen this or, even better, know a way around it?

Running without a terminology server (-tx n/a) does not lead to the above error. However, I see that using this option now itself causes the validation to fail (Error validating code: running without terminology services), which I do not quite understand. After all, I explicitly switched it off and the validator outputs a large warning about this at the top, so why is this also a validation error for the resource? Is there now some other way to switch of terminology checks without causing an error (e.g. to avoid a CI pipeline with automatic validation breaking if no terminology server is available)?

Grahame Grieve (Oct 15 2018 at 13:01):

do you get a stack dump?

Morten Ernebjerg (Oct 15 2018 at 14:04):

I only get the output I pasted in above (not sure how I can convince the JVM to say more...)

Michael Riley (Oct 15 2018 at 14:52):

Without knowing how you ran the validator, this looks like a FHIR version issue. That's an R4 (release candidate 4/STU4) class, so it shouldn't be used to validate STU3 resources. The right class would be org.hl7.fhir.dstu3.model.Parameters.

Unless I'm misunderstanding and you intended to validate R4 resources?

Grahame Grieve (Oct 15 2018 at 17:54):

this is a bug in the validator. I'm mystified how this passes the JUnit tests that are part of the build that run exactly this test. because due to a bug in my code this will fail.