I am using Helidon 2.5.x and I see some warning messages logged sporadically like below:
"Deserialization attempted for class oracle.sql.converter.CharacterConverter1Byte, yet there is no global serial filter configured. To automatically configure a filter, please set system property \"helidon.serialFilter.missing.action\" to \"configure\"",
The message is a warning without a stack trace context - so I am unable to correlate this with any SQL execution to narrow down the problem. A general Github source search indicates it is from SerializationConfig in Helidon common. The error seems to be logged only on certain VMs only when connecting to Oracle DB - however I could be wrong here.
The key mentioned in the message “helidon.serialFilter.missing.action" seems to be undocumented. What is the warning trying to tell me, and why should I be setting this additional system property? More importantly, what am I dodging by following the instructions to set the system property?
Is it a recommended solution to set the property? Where is this documented?
Here is the documentation for Helidon 3.x which should pretty much apply to 2.x: https://helidon.io/docs/v3/#/se/security/jep-290 (the main change between 2.x and 3.x is defaults I think).
You can see an example serial-config.properties file here https://github.com/helidon-io/helidon/blob/3.2.0/examples/integrations/oci/atp-cdi/src/main/resources/META-INF/helidon/serial-config.properties