[ARROW-485] [Java] Users are required to initialize VariableLengthVectors.offsetVector before calling VariableLengthVectors.mutator.getSafe

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.2.0
• Component/s: Java
• External issue URL: https://github.com/apache/arrow/issues/16128
• Assignee: Unassigned
• Reporter: Li Jin
• Created: 14/Jan/17 06:41
• Updated: 11/Jan/23 07:09
• Resolved: 17/Jan/17 19:54

Description

https://github.com/apache/arrow/blob/master/java/vector/src/main/codegen/templates/VariableLengthVectors.java#L492

Here VariableLengthVectors.getMutator().setSafe() calls:

offsetVector.getAccessor().get(index)

however, index 0 of offsetVector (which is always 0) is not initialized by VariableLengthVectors.

As a result, user of the VariableLengthVectors needs to manually initialize
the class by calling:

VariableLengthVectors.getOffsetVector().getMutator().setSafe(0, 0)

I wonder if this is necessary or should VariableLengthVectors initialize this for the user