The org.apache.flink.streaming.api.operators.collect.CollectSinkFunction function does not define a serialVersionUID.
Function objects are serialized using Java Serialization and should define a serialVersionUID.
If no o serialVersionUID is defined, Java automatically generates IDs to check compatibility of objects during deserialization. However, the generation depends on the environment (JVM, class version, etc.) and can hence lead to java.io.InvalidClassException even if the classes are compatible.