chore: add code comment for spec entity

[tomsun28]

Description

Referring to https://a2aproject.github.io/A2A/latest/specification/, add comments to the entity code of the spec.

• Follow the CONTRIBUTING Guide.
• Make your Pull Request title in the https://www.conventionalcommits.org/ specification.
  • Important Prefixes for release-please:
    • fix: which represents bug fixes, and correlates to a SemVer patch.
    • feat: represents a new feature, and correlates to a SemVer minor.
    • feat!:, or fix!:, refactor!:, etc., which represent a breaking change (indicated by the !) and will result in a SemVer major.
• Ensure the tests pass
• Appropriate READMEs were updated (if necessary)

Fixes #<issue_number_goes_here> 🦕

[gemini-code-assist]

Summary of Changes

Hello @tomsun28, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the documentation of the A2A specification's core Java entity classes. By adding comprehensive Javadoc comments to classes, interfaces, records, enums, and their members, it aims to improve code readability, maintainability, and adherence to the official A2A specification, making it easier for developers to understand and utilize the protocol entities.

Highlights

• Documentation Enhancement: Added comprehensive Javadoc comments to all core Java entity classes, interfaces, records, and enums within the spec module. This includes detailed explanations for classes, constructors, methods, fields, and nested types.
• Specification Alignment: Ensured that the newly added code comments align with the official A2A specification, providing clear and consistent documentation for developers using the protocol entities.
• Code Readability: Improved the overall readability and maintainability of the spec module by providing inline documentation that clarifies the purpose, usage, parameters, and return values of each component.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point in your pull request via creating an issue comment (i.e. comment on the pull request page) using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in issue comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist is currently in preview and may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments to provide feedback.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

[gemini-code-assist]

Code Review

This pull request adds comprehensive Javadoc comments across numerous entity classes in the io.a2a.spec package, significantly improving code documentation and clarity. The added comments are well-written and accurately describe the purpose of the classes, methods, and fields. I've identified one minor inaccuracy in the Javadoc for A2AClientHTTPError which I've commented on. Otherwise, the changes look great.