Motivation and Context

DynamoDB allows attribute names up to 65,535 bytes(docs), but Jackson's default StreamReadConstraints.maxNameLength of 50,000 causes StreamConstraintsException when the SDK deserializes responses containing attribute names longer than 50K characters. Since Jackson is shaded inside the SDK, customers cannot override this setting.

Modifications

• Override maxNameLength to 65,535 in AwsStructuredPlainJsonFactory.JSON_FACTORY to match the DynamoDB service limit. This is the JsonFactory used by all JSON-protocol service clients.

Testing

• Added unit test in AwsStructuredPlainJsonFactoryTest verifying the JsonFactory can parse a 65,535-char
  field name.
• Added WireMock integration test in LongAttributeNameTest (sync + async clients) that stubs a DynamoDB
  GetItem response with a 65,535-char attribute name and verifies end-to-end deserialization succeeds.
• Ran one-off integration test against real DynamoDB with attribute names of 50,001 and 65,535 characters.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist

• I have read the CONTRIBUTING
  document
• Local run of mvn install succeeds
• My code follows the code style of this project
• My change requires a change to the Javadoc documentation
• I have updated the Javadoc documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed
• I have added a changelog entry. Adding a new entry must be accomplished by running the
  scripts/new-change script and following the instructions. Commit the new file created by the script in
  .changes/next-release with your changes.

License

• I confirm that this pull request can be released under the Apache 2 license