Logging Filter Actions
You can turn on logging to record the initialization, rejections, and acceptances of calls to serialization filters. Use the log output as a diagnostic tool to see what's being deserialized, and to confirm your settings when you configure allow-lists and reject-lists.
When logging is enabled, filter actions are logged to the java.io.serialization logger.
To enable serialization filter logging, edit the $JDK_HOME/conf/logging.properties
file.
To log calls that are rejected, add
java.io.serialization.level = FINE
To log all filter results, add
java.io.serialization.level = FINEST