Hi to all, I'd like to join 2 datasets of POJO, let's say for example:
Person: - name - birthPlaceId Place: - id - name I'd like to do people.coCoGroup(places).where("birthPlaceId").equalTo("id").with(...) However, not all people have a birthPlaceId value in my use case..so I get a NullPointer. Am I using the wrong operator for this? This is the stackTrace: java.lang.RuntimeException: A NullPointerException occured while accessing a key field in a POJO. Most likely, the value grouped/joined on is null. Field name: birthPlaceId at org.apache.flink.api.java.typeutils.runtime.PojoComparator.hash(PojoComparator.java:217) at org.apache.flink.runtime.operators.shipping.OutputEmitter.hashPartitionDefault(OutputEmitter.java:175) at org.apache.flink.runtime.operators.shipping.OutputEmitter.selectChannels(OutputEmitter.java:132) at org.apache.flink.runtime.operators.shipping.OutputEmitter.selectChannels(OutputEmitter.java:28) at org.apache.flink.runtime.io.network.api.writer.RecordWriter.emit(RecordWriter.java:78) at org.apache.flink.runtime.operators.shipping.OutputCollector.collect(OutputCollector.java:65) Best, Flavio