fix(a2a): prevent a2a SDK SPI loading issues caused by delayed thread…

[LearningGp]

AgentScope-Java Version

1.0.8

Description

Same as #464

Checklist

Please check the following items before code is ready to be reviewed.

• Code has been formatted with mvn spotless:apply
• All tests are passing (mvn test)
• Javadoc comments are complete and follow project conventions
• Related documentation has been updated (e.g. links, examples, etc.)
• Code is ready for review

[gemini-code-assist]

Summary of Changes

Hello @LearningGp, 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 addresses a critical issue affecting A2A SDK SPI loading by refining the thread management for HTTP stream processing. By ensuring that stream operations are executed on a dedicated bounded elastic scheduler, the change mitigates problems caused by delayed threads, thereby enhancing the stability and reliability of the SDK's initialization and operation.

Highlights

• Thread Scheduling for Stream Processing: Introduced publishOn(Schedulers.boundedElastic()) to explicitly manage the thread on which streaming HTTP responses are processed. This change aims to prevent issues related to delayed threads that could impact A2A SDK SPI loading.

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[gemini-code-assist]

Code Review

This pull request attempts to fix a threading issue by introducing publishOn to a reactive stream. While the intent is correct, the placement of the operator doesn't fully resolve the potential for blocking an HttpClient thread. My review includes a suggestion to adjust the operator order to correctly offload the blocking I/O operation, preventing potential thread starvation in the HTTP client's thread pool.

[Copilot]

Pull request overview

This PR fixes SPI (Service Provider Interface) loading issues in the a2a SDK by ensuring reactive streams emit events on threads with the correct context classloader. The issue was caused by delayed thread switching in the reactive pipeline, which prevented ServiceLoader from properly loading transport implementations.

Changes:

• Added .publishOn(Schedulers.boundedElastic()) to the reactive stream chain in JdkHttpTransport.stream() to ensure downstream subscribers receive events on a thread with the correct context classloader

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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