Storing null values in avro files

user_2730024 0
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I have some json data that looks like this:

  {
    "id": 1998983092,
    "name": "Test Name 1",
    "type": "search string",
    "creationDate": "2017-06-06T13:49:15.091+0000",
    "lastModificationDate": "2017-06-28T14:53:19.698+0000",
    "lastModifiedUsername": "testuser@test.com",
    "lockedQuery": false,
    "lockedByUsername": null
  }

I am able to add the lockedQuery null value to a GenericRecord object without issue.

GenericRecord record = new GenericData.Record(schema);
if(json.isNull("lockedQuery")){
    record.put("lockedQuery", null);
}

However, later when I attempt to write that GenericRecord object to an avro file I get a null pointer exception.

File file = new File("~/test.arvo");
DatumWriter<GenericRecord> datumWriter = new GenericDatumWriter<>(schema);
DataFileWriter<GenericRecord> dataFileWriter = new DataFileWriter<>(datumWriter);
dataFileWriter.create(schema, file);
for(GenericRecord record: masterList) {
    dataFileWriter.append(record); // NULL POINTER HERE
}

When I run that code I get the following exception. Any tips on how to process a null value into an Avro file much appreciated. Thanks in advance.

java.lang.NullPointerException: null of boolean in field lockedQuery of 
com.mydomain.test1.domain.MyAvroRecord
Exception in thread "main" java.lang.RuntimeException: 
org.apache.avro.file.DataFileWriter$AppendWriteException: 
java.lang.NullPointerException: null of boolean in field lockedQuery of 
com.mydomain.test1.domain.MyAvroRecord
at com.mydomain.avro.App.main(App.java:198)
Caused by: org.apache.avro.file.DataFileWriter$AppendWriteException: 
java.lang.NullPointerException: null of boolean in field lockedQuery of 
com.mydomain.test1.domain.MyAvroRecord
at org.apache.avro.file.DataFileWriter.append(DataFileWriter.java:308)

EDIT: here is the MyAvroRecord

public class MyAvroRecord {
    long id;
    String name;
    String type;
    Date timestamp;
    Date lastModifcationDate;
    String lastModifiedUsername;
    Boolean lockedQuery;
avro-tools avro java
2 Answers

I have this issue too and now resolved it.

I found @Nullable annotation in Apache Avro to declare the field is nullable.

So, in this example, we should

import org.apache.avro.reflect.Nullable;

public class MyAvroRecord {
    long id;
    String name;
    String type;
    Date timestamp;
    Date lastModifcationDate;
    String lastModifiedUsername;
    @Nullable
    Boolean lockedQuery;
}
user_103907050
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