AVRO-2885: [Java] better check int vs float value

[clesaec]

What is the purpose of the change

AVRO-2885 : check non int value on JsonDecoder (accept only real int or float value as 1.0, when conversion to int doesn't modify the value.

Verifying this change

One new unit test TestJsonDecoder.testIntWithError; to ensure that value -1.2 to read an int will throw an error.

Documentation

• Does this pull request introduce a new feature? (no)
• If yes, how is the feature documented? (not applicable)

[KalleOlaviNiemitalo]

What's the behaviour if you encode 1.2 to Avro binary format using a record schema with a floating-point field, and then decode it with a reader schema that has an int field? Based on Schema Resolution, I'd expect that to be an error: "int is promotable to long, float, or double" but not vice versa. If that indeed is an error, then it makes sense that decoding an int from JSON 1.2 should likewise be an error.

[clesaec]

Indeed, with binary decoder, it sends an AvroTypeException, "Found float, expecting int".
With this JIRA; it's also the case for json decoder. Float value 1.2 generate an error when trying to put it in an avro int field; while 1 or 1.0 json value will succeed to be translated in 1 int value.