Infinite training loop

[nruemmele]

This issue appears only if we want logging in DEBUG mode.
In such case we get Spark+json4s incompatibility issue which raises
java.lang.NoSuchMethodError: org.json4s.jackson.JsonMethods$.render(Lorg/json4s/JsonAST$JValue;)Lorg/json4s/JsonAST$JValue

However, this error is not caught by schema-matcher-api or DINT code. The model will get into the eternal "busy" state if we try to train it.

[arc0]

https://jira.csiro.au/browse/SERENE-169

[HJW577X]

Hello, I've encountered a problem. The model has completed training but is always busy. I think it may be the same as your problem, but I don't know which version to modify