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Type:
Bug
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Resolution: Done
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Priority:
Major - P3
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Affects Version/s: 3.3.0
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Component/s: Query Operations
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None
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Environment:MongoDB server 3.2.8
Windows 7 x64
java version "1.8.0_45"
Java(TM) SE Runtime Environment (build 1.8.0_45-b15)
Java HotSpot(TM) 64-Bit Server VM (build 25.45-b02, mixed mode)
Using the async Java driver and running a `distinct` query over a string-typed field that may contain null values results in `org.bson.BsonInvalidOperationException` being thrown. Example code using the `distinct` query operation, sanitized and simplified:
mongoCollection .distinct("stringFieldName", String.class) .into(new ArrayList<String>(), asyncCallback)
A workaround is available to filter out null values:
mongoCollection .distinct("stringFieldName", Filters.ne("stringFieldName", new BsonNull()), String.class) .into(new ArrayList<String>(), asyncCallback)
Exception:
org.bson.BsonInvalidOperationException: readString can only be called when CurrentBSONType is STRING, not when CurrentBSONType is NULL. at org.bson.AbstractBsonReader.verifyBSONType(AbstractBsonReader.java:655) at org.bson.AbstractBsonReader.checkPreconditions(AbstractBsonReader.java:687) at org.bson.AbstractBsonReader.readString(AbstractBsonReader.java:428) at org.bson.codecs.StringCodec.decode(StringCodec.java:39) at org.bson.codecs.StringCodec.decode(StringCodec.java:28) at com.mongodb.operation.CommandResultArrayCodec.decode(CommandResultArrayCodec.java:48) at com.mongodb.operation.CommandResultDocumentCodec.readValue(CommandResultDocumentCodec.java:53) at org.bson.codecs.BsonDocumentCodec.decode(BsonDocumentCodec.java:84) at org.bson.codecs.BsonDocumentCodec.decode(BsonDocumentCodec.java:41) at com.mongodb.connection.ReplyMessage.<init>(ReplyMessage.java:57) at com.mongodb.connection.CommandProtocol.getResponseDocument(CommandProtocol.java:139)