Make DefaultSdkAutoConstructList/Map Serializable.

[ryucc]

Motivation and Context

See Issue #3143

Classes AttributeValue, S3Object, DynamoDb GetItemRequest implement the Serializable interface, but throws a NotSerializableException since v2.

This is due to using DefaultSdkAutoConstructList/Map as member field. When a Map/List does not exist in the request, These DefaultSdkAutoConstruct represent the non-existence, in contrary to an existing but empty List/Map.

There is a 4 line fix, to make these 2 classes Serializable. The challenge here is that they are both singleton classes. Java provides a readResolve() interface to handle this case.

The official documentation is here:
https://docs.oracle.com/en/java/javase/17/docs/specs/serialization/input.html

Other 3rd party references:
https://www.baeldung.com/java-serialization-readobject-vs-readresolve
https://stackoverflow.com/questions/3930181/how-to-deal-with-singleton-along-with-serialization

This feature is available since java 8:
https://docs.oracle.com/javase/8/docs/api/java/io/Serializable.html

Modifications

Make DefaultSdkAutoConstructList/Map Serializable.

• Add the Serializable to both classes
• Implement the readResolve() method, to return the singleton INSTANCE.
• Add unit test, testing serialization/deserialization is working, and the deserialized result is not a new instance.

Testing

• New unit tests implemented

java version "1.8.0_441"
Java(TM) SE Runtime Environment (build 1.8.0_441-b07)
Java HotSpot(TM) 64-Bit Server VM (build 25.441-b07, mixed mode)
Darwin **** 23.4.0 Darwin Kernel Version 23.4.0: Fri Mar 15 00:19:22 PDT 2024; root:xnu-10063.101.17~1/RELEASE_ARM64_T8112 arm64

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

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.
• My change is to implement 1.11 parity feature and I have updated LaunchChangelog

License

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