[Java] Add JSON read/write support for decimals for integration tests

[asfimport]

Reporter: Bryan Cutler / @BryanCutler
Assignee: Bryan Cutler / @BryanCutler

Related issues:

• Integration tests for Decimal types (blocks)
• Add decimal type support to ArrowWriter. (is related to)

_{Note: This issue was originally created as ARROW-1238. Please see the migration documentation for further details.}

[asfimport]

Bryan Cutler / @BryanCutler:
I can get started on this to be ready for integration tests

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Wes McKinney / @wesm:
This is getting pretty close to being needed. @icexelloss may be able to look at this if @BryanCutler is not able

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Li Jin / @icexelloss:
I can take a look if @BryanCutler is not available. What's the json format for decimals?

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Wes McKinney / @wesm:
I think we should encode as hexadecimal like with binary types. The metadata probably needs the precision, scale, and bit width

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Bryan Cutler / @BryanCutler:
It would be really great to get integration tests for decimal in for the next release. I should be able to get this done in the next couple of days, if not then I'll ping you @icexelloss.

[asfimport]

Wes McKinney / @wesm:
Issue resolved by pull request 994
#994