Solon 4.0.3 Released: AI Loop, Code Talent, JDK 25 Prep

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On July 2, 2026, the Solon team released v4.0.3 — just 22 days after v4.0.0 and 7 days after v4.0.2. Three releases in under a month. The pace tells a clear story: Solon's iteration speed is accelerating, and the focus is firmly on AI Agent infrastructure.

Here's what's new and why it matters.


What's in v4.0.3

Category Change Description
🆕 New solon-ai-loop AI loop execution module for iterative agent reasoning
🆕 New solon-ai-talent-code Code talent plugin, extracted from solon-ai-harness
🆕 New ScopeLocal.Factory interface More flexible scoped variable factory
🆕 New ScopeLocalJdk25 auto-load JDK 25 scoped values support, auto-detected
🔧 Adjust Restored BeanContainer.wrapPublish Transition compatibility buffer
🔧 Adjust Restored ResourceUtil.scanClasses Same, giving ecosystem plugins time to migrate

The Three Changes That Matter Most

1. solon-ai-loop: The Agent's "Iteration Engine"

This is the most significant new module in this release.

What problem does it solve?

In ReActAgent and TeamAgent, reasoning steps are linear — think, act, observe, done. But many real-world scenarios require agents to loop:

  • Code generation: write code → compile fails → read error → fix → recompile → until green
  • Automated testing: write tests → run → analyze failure → fix → rerun → until pass
  • Data cleaning: clean → validation fails → adjust params → clean again → verify → until合格

solon-ai-loop provides a controlled loop execution framework, allowing agents to iterate until a termination condition is met. It works with the existing StopLoopInterceptor to control max iterations, timeouts, and even manual interruption.

2. solon-ai-talent-code: Code Abilities as a Standalone Module

Before v4.0.3, code-related talents (file reading/writing, shell execution, LSP analysis, etc.) were bundled inside Harness. If you only needed ChatModel + code abilities, you had to pull in the entire Harness.

Now solon-ai-talent-code is independent, giving you a lightweight, focused dependency:

<!-- Code abilities only, no Harness needed -->
<dependency>
    <groupId>org.noear</groupId>
    <artifactId>solon-ai-talent-code</artifactId>
    <version>4.0.3</version>
</dependency>
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This makes Harness leaner, and makes code talents reusable in other contexts — like SolonCode CLI, which is itself Harness-driven.

3. JDK 25 ScopeLocal Auto-Loading

JDK 25 is the upcoming LTS release (September 2026), and Solon has a tradition of pre-adapting before the official JDK release.

The ScopeLocalJdk25 auto-load mechanism means: when you upgrade to JDK 25, Solon automatically switches to JDK 25's scoped value implementation — zero code changes, zero config.

This is "compatible with Java 8 ~ Java 25" in action — not just running on new JDKs, but actually leveraging their capabilities.


From M1 to GA: 11 Days

v4.0.3-M1 (milestone) was released in late June 2026, and it took just 11 days to reach GA status.

The v4.0.x release cadence:

Version Date Interval
v4.0.0 2026-06-10 -
v4.0.2 2026-06-25 15 days
v4.0.3-M1 2026-06-late ~5 days
v4.0.3 2026-07-02 ~11 days (incl. M1)

Three GA releases in under four months tells us two things:

  1. The v4.x core stack is stable — each release is incremental, not firefighting
  2. AI ecosystem is the primary iteration focus — all three releases center on AI modules

v4.0.x LTS Support

Per the official LTS plan (solon.noear.org/article/lts):

Dimension Timeline
Initial release 2026-06
Open-source support ends 2026-12
Commercial support ends 2029-06 (3 years)

v4.0.x is the current main line, with full LTS guarantees. Expect a minor release roughly every 20 days, with each minor version line having independent LTS maintenance.

If you're on v3.x in production, v3.10.x is still actively maintained — no rush to migrate.


What This Means for the AI Ecosystem

Modularization Progressing

v4.0.0 → skill renamed to talent (unified naming)
v4.0.2 → multiple new AI plugins added
v4.0.3 → talent-code extracted, AI Loop added
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Solon AI's modularization follows a "unify then split" pattern — first standardize the concepts, then extract reusable modules.

Loop Capability Filled

Previously, Solon AI lacked a loop abstraction. Developers had to write custom loop logic inside onObservation, leading to code duplication and poor control over termination, timeout, and resource cleanup.

solon-ai-loop fills this gap. Combined with StopLoopInterceptor, you now have clean, controlled iteration:

// Conceptual example
Harness.harness(agent)
    .addInterceptor(new StopLoopInterceptor(maxIterations))
    .loop(context -> {
        return agent.step(context);
    })
    .start();
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Paving the Way for SolonCode

The extraction of solon-ai-talent-code directly benefits SolonCode CLI — Solon's AI coding assistant. SolonCode is Harness-driven under the hood. With code talents as a standalone module, SolonCode can depend on talent-code without pulling in the full Harness weight, improving CLI startup time and reducing package size.


Upgrade Path

New Projects

Start directly with v4.0.3:

<dependency>
    <groupId>org.noear</groupId>
    <artifactId>solon</artifactId>
    <version>4.0.3</version>
</dependency>
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From v4.0.2

Compatible upgrade — just bump the version number. No breaking changes.

From v4.0.0

If you're still using the old solon-ai-skill-* package names (pre-v4.0.0), migrate to solon-ai-talent-*. The migration guide was published alongside v4.0.0.

From v3.x

v3.x → v4.x changes are concentrated in AI modules and package restructuring. The core framework (solon, solon-web, etc.) is largely compatible. Validate on a test project first.


What's Next

Based on the current iteration direction and community discussions:

  1. solon-ai-talent-code will continue evolving — expect deeper LSP integration and Git operations
  2. MCP protocol tracking — the MCP protocol itself is evolving fast, Solon will keep pace
  3. v4.0.4 is already on the roadmap — roughly late July at the current cadence

Final Thoughts

v4.0.3 isn't a "big" release. But it's a revealing one: the Solon team is using high-frequency iteration to rapidly fill capability gaps in the AI ecosystem.

In the 22 days from v4.0.0 to v4.0.3, we've seen:

  • Unified naming (skill → talent)
  • Core capabilities extracted (talent-code)
  • Loop engine built (AI Loop)
  • Next-gen JDK support (JDK 25)

Each release is small. But each one moves the needle.


Links

Source: dev.to

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