[AVRO-1949] Not setting a non-null field in GenericRecord causes a NullPointer exception on Serialisation even though a default is defined in the schema

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Duplicate
• Affects Version/s: 1.8.1
• Component/s: java

Environment

Windows 7, JDK8

• Assignee: Unassigned
• Reporter: Mike Hurd
• Created: 04/Nov/16 09:13
• Updated: 04/Nov/16 11:22
• Resolved: 04/Nov/16 11:22

Description

As per the summary, I had a search through the existing JIRAs but couldn't find a match apologies if this is a duplicate:

example schema:

{"namespace": "example.data",
  "type": "record",
  "name": "Data",
  "fields": [
    {"name": "name", "type": "string"},
    {"name": "favorite_season", "type": "string", "default": "Autumn"}
  ]
}

GenericRecord record = new GenericData.Record(schema);
record.put("name", "my name");

Serialising the above throws a NullPointerException:

java.lang.NullPointerException: null of string in field favorite_season of example.data.Data
	at org.apache.avro.generic.GenericDatumWriter.npe(GenericDatumWriter.java:145) ~[classes/:?]
	at org.apache.avro.generic.GenericDatumWriter.writeWithoutConversion(GenericDatumWriter.java:139) ~[classes/:?]
	at org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:75) ~[classes/:?]
	at org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:62) ~[classes/:?]

Surely, given that the schema is available the writeField method should check to see if there is a default field available to use if the required field does not have a value supplied (and is not-null).