Hi folks, I have two questions about types in Flink when using Scala:
1. scala case class: This my case class define: case class SensorReading(var id: String , var timestamp: Long, var temperature: Double) In documentation, Scala case class is supported: `Scala case classes (including Scala tuples): null fields not supported` But the log info shows: 10:26:08,489 INFO org.apache.flink.api.java.typeutils.TypeExtractor - class io.github.streamingwithflink.util.SensorReading is missing a default constructor so it cannot be used as a POJO type and must be processed as GenericType. Please read the Flink documentation on "Data Types & Serialization" for details of the effect on performance. 2. scala list This my case class define: case class SensorReading(var id: String , var timestamp: Long, var temperature: Double, var list: List[String] = List[String]()) log shows: No fields were detected for class scala.collection.immutable.List so it cannot be used as a POJO type and must be processed as GenericType. Please read the Flink documentation on "Data Types & Serialization" for details of the effect on performance. Does it means that scala list can be serialize that I can ignore this info if I don’t care the performance. Should I use Java array list instead of scala list or create a custom serializer for SensorReading case class? Thanks! Best regards Utopia
