Alex Black created ARROW-3175:
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Summary: Arrow Java: Upgrade to official FlatBuffers release
(Flatbuffers incompatibility)
Key: ARROW-3175
URL: https://issues.apache.org/jira/browse/ARROW-3175
Project: Apache Arrow
Issue Type: Bug
Components: Java
Affects Versions: 0.10.0
Reporter: Alex Black
Arrow Java currently uses an unofficial flatbuffers dependency -
com.vlkan:flatbuffers:
[https://github.com/apache/arrow/blob/master/java/pom.xml#L481-L485]
The likely motivation here is that previously, no Java flatbuffers
implementation was available on maven central.
[https://github.com/vy/flatbuffers]
> Unfortunately, FlatBuffers project does not publish any artifacts to the
> Maven Central Repository
However, this is no longer the case:
[https://search.maven.org/search?q=g:com.google.flatbuffers%20AND%20a:flatbuffers-java&core=gav]
The flatbuffers version used in Arrow java is a nearly 3-year-old snapshot, not
even a version of an official release: [https://github.com/vy/flatbuffers#usage]
The main problem is that this version of flatbuffers is not compatible with the
official releases of flatbuffers.
For example, we use the official flatbuffers releases in ND4J and
Deeplearning4j: [https://github.com/deeplearning4j/deeplearning4j]
Running Arrow with an official flatbuffers library on the classpath results in
issues such as:
{noformat}
java.lang.NoSuchMethodError:
com.google.flatbuffers.FlatBufferBuilder.createString(Ljava/lang/String;)I
at org.apache.arrow.vector.types.pojo.Field.getField(Field.java:154)
at org.apache.arrow.vector.types.pojo.Schema.getSchema(Schema.java:145)
at
org.apache.arrow.vector.ipc.message.MessageSerializer.serialize(MessageSerializer.java:124)
at org.apache.arrow.vector.ipc.ArrowWriter.ensureStarted(ArrowWriter.java:136)
at org.apache.arrow.vector.ipc.ArrowWriter.start(ArrowWriter.java:97)
at FlatBuffersDependencyIssue.test(FlatBuffersDependencyIssue.java:56)
{noformat}
Simply excluding the com.vlkan:flatbuffers dependency in lieu of an official
flatbuffers release is not a solution (same exception as above) and we aren't
prepared to downgrade all of our projects to use the flatbuffers version that
Arrow currently requires.
Consequently, this is a major issue that prevents us using Arrow in our
libraries.
I have prepared a simple repository to reproduce this issue, if required:
[https://github.com/AlexDBlack/arrowflatbufferstest]
Is there a reason for using this particular version of flatbuffers, and if not,
can Arrow java use an official release of flatbuffers instead?
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