build: replace Checkstyle with Spotless (google-java-format)

Signed-off-by: Emmanuel Hugonnet <ehugonne@redhat.com>

Author: ehsavoie

.github/workflows/build-and-test.yml

@@ -16,6 +16,18 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
+  spotless:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
+      - name: Set up JDK 21
+        uses: actions/setup-java@b843ebf9b913146b38da2eaa7aeddf76074ae1ad # v6
+        with:
+          java-version: '21'
+          distribution: 'temurin'
+          cache: maven
+      - name: Check formatting with Spotless
+        run: mvn -B spotless:check -Dskip.spotless=false --file pom.xml
   build:
     runs-on: ${{ matrix.os }}
     strategy:

AGENTS.md

@@ -20,28 +20,28 @@ mvn clean install
 - `spec-grpc/` — gRPC protobuf definitions and generated classes
 - `common/` — Shared utilities used across modules
 - `client/` — Client SDK
-  - `base/` — Core client API
-  - `transport/spi/` — Transport SPI
-  - `transport/jsonrpc/`, `transport/grpc/`, `transport/rest/` — Transport implementations
+- `base/` — Core client API
+- `transport/spi/` — Transport SPI
+- `transport/jsonrpc/`, `transport/grpc/`, `transport/rest/` — Transport implementations
 - `server-common/` — Server-side core (AgentExecutor, TaskStore, QueueManager)
 - `transport/` — Server transport layer (jsonrpc, grpc, rest)
 - `http-client/` — HTTP client abstraction
 - `jsonrpc-common/` — Shared JSON-RPC utilities
 - `reference/` — Reference server implementations built on Quarkus
-  - `common/`, `jsonrpc/`, `grpc/`, `rest/`
-  - `multiversion-jsonrpc/`, `multiversion-rest/` — Multi-version dispatching (v1.0 + v0.3)
+- `common/`, `jsonrpc/`, `grpc/`, `rest/`
+- `multiversion-jsonrpc/`, `multiversion-rest/` — Multi-version dispatching (v1.0 + v0.3)
 - `tck/` — Technology Compatibility Kit (protocol conformance tests)
 - `tests/` — Integration and server-common tests
-  - `server-common/` — Server-common integration tests
-  - `multiversion/` — Multi-version integration tests (jsonrpc, rest, grpc)
+- `server-common/` — Server-common integration tests
+- `multiversion/` — Multi-version integration tests (jsonrpc, rest, grpc)
 - `extras/` — Optional add-ons
-  - `common/` — Shared classes across extras modules
-  - `opentelemetry/` — OpenTelemetry integration
-  - `task-store-database-jpa/` — JPA-backed task store
-  - `push-notification-config-store-database-jpa/` — JPA-backed push notification config store
-  - `queue-manager-replicated/` — Kafka-based replicated queue manager
-  - `http-client-vertx/` — Vert.x HTTP client
-  - `http-client-android/` — Android HTTP client
+- `common/` — Shared classes across extras modules
+- `opentelemetry/` — OpenTelemetry integration
+- `task-store-database-jpa/` — JPA-backed task store
+- `push-notification-config-store-database-jpa/` — JPA-backed push notification config store
+- `queue-manager-replicated/` — Kafka-based replicated queue manager
+- `http-client-vertx/` — Vert.x HTTP client
+- `http-client-android/` — Android HTTP client
 - `compat-0.3/` — Backward compatibility layer for A2A protocol v0.3
 - `integrations/` — Runtime integrations (e.g., MicroProfile Config)
 - `test-utils-docker/` — Test utilities for conditional Docker-based test execution
@@ -117,12 +117,12 @@ mvn quarkus:dev
 For detailed architectural documentation:
 
 - **EventQueue & Event Processing**: `.claude/architecture/EVENTQUEUE.md`
-  - Quick reference with architecture diagram and core components
-  - **[Queue Lifecycle](.claude/architecture/eventqueue/LIFECYCLE.md)**: Two-level protection, fire-and-forget, late reconnections
-  - **[Request Flows](.claude/architecture/eventqueue/FLOWS.md)**: Non-streaming vs streaming, cleanup patterns
-  - **[Usage Scenarios](.claude/architecture/eventqueue/SCENARIOS.md)**: Real-world patterns and common pitfalls
+- Quick reference with architecture diagram and core components
+- **[Queue Lifecycle](.claude/architecture/eventqueue/LIFECYCLE.md)**: Two-level protection, fire-and-forget, late reconnections
+- **[Request Flows](.claude/architecture/eventqueue/FLOWS.md)**: Non-streaming vs streaming, cleanup patterns
+- **[Usage Scenarios](.claude/architecture/eventqueue/SCENARIOS.md)**: Real-world patterns and common pitfalls
 - **Compatibility with previous protocol versions**:
-  - 0.3 protocol compatibility layer: `.claude/architecture/compatibility_0.3.md`
+- 0.3 protocol compatibility layer: `.claude/architecture/compatibility_0.3.md`
 
 > 💡 Deep-dive docs are loaded on-demand when working in related areas.
 

CODE_OF_CONDUCT.md

@@ -21,20 +21,20 @@ community include:
 * Being respectful of differing opinions, viewpoints, and experiences
 * Giving and gracefully accepting constructive feedback
 * Accepting responsibility and apologizing to those affected by our mistakes,
-  and learning from the experience
+and learning from the experience
 * Focusing on what is best not just for us as individuals, but for the overall
-  community
+community
 
 Examples of unacceptable behavior include:
 
 * The use of sexualized language or imagery, and sexual attention or advances of
-  any kind
+any kind
 * Trolling, insulting or derogatory comments, and personal or political attacks
 * Public or private harassment
 * Publishing others' private information, such as a physical or email address,
-  without their explicit permission
+without their explicit permission
 * Other conduct which could reasonably be considered inappropriate in a
-  professional setting
+professional setting
 
 ## Enforcement Responsibilities
 

CONTRIBUTING.md

@@ -5,7 +5,7 @@ Welcome to the A2A Java SDK project! We welcome contributions from the community
 
 - [Forking the Project](#forking-the-project)
 - [Issues](#issues)
-    - [Good First Issues](#good-first-issues)
+	- [Good First Issues](#good-first-issues)
 - [Setting up your Developer Environment](#setting-up-your-developer-environment)
 - [Contributing Guidelines](#contributing-guidelines)
 - [Community](#community)
@@ -55,21 +55,21 @@ To set up your development environment you need to:
 
 2. Add a remote ref to upstream, for pulling future updates. For example:
 
-    ```
-    git remote add upstream https://github.com/a2aproject/a2a-java
-    ```
+	```
+	git remote add upstream https://github.com/a2aproject/a2a-java
+	```
 
 3. To build `a2a-java` and run the tests, use the following command:
 
-    ```
-    mvn clean install
-    ```
+	```
+	mvn clean install
+	```
 
 4. To skip the tests:
 
-    ```
-    mvn clean install -DskipTests=true
-    ```
+	```
+	mvn clean install -DskipTests=true
+	```
 
 ## Contributing Guidelines
 
@@ -78,7 +78,7 @@ When submitting a PR, please keep the following guidelines in mind:
 1. In general, it's good practice to squash all of your commits into a single commit. For larger changes, it's ok to have multiple meaningful commits. If you need help with squashing your commits, feel free to ask us how to do this on your pull request. We're more than happy to help!
 
 2. Please link the issue you worked on in the description of your pull request and in your commit message. For example, for issue-20, the PR description and commit message could be: ```Add tests to A2AClientTest for sending a task with a FilePart and with a DataPart
- Fixes #20```
+Fixes #20```
 
 3. Your PR should include tests for the functionality that you are adding.
 

CONTRIBUTING_INTEGRATIONS.md

@@ -7,9 +7,9 @@ The pull request should contain a link to your project page.
 Then the project page itself needs to contain the following information as a minimum:
 
 * How to use the integration.
-   * Ideally there should be a sample demonstrating how to use it 
+* Ideally there should be a sample demonstrating how to use it
 * The integration should have tests, extending [AbstractA2AServerTest](tests/server-common/src/test/java/org/a2aproject/sdk/server/apps/common/AbstractA2AServerTest.java)
 * The integration should pass the [TCK](https://github.com/a2aproject/a2a-tck), and make it obvious how to see that it has passed.
 * Ideally, the integration should be deployed in Maven Central. If that is not possible, provide clear instructions for how to build it.
 
-If some of the above points are problematic, feel free to point that out in your pull request, and we can discuss further. For example, AbstractA2AServerTest is currently written with only the initial runtimes in mind, and might need some tweaking.
+If some of the above points are problematic, feel free to point that out in your pull request, and we can discuss further. For example, AbstractA2AServerTest is currently written with only the initial runtimes in mind, and might need some tweaking.

README.md

@@ -5,10 +5,10 @@
 <!-- markdownlint-disable no-inline-html -->
 
 <html>
-   <h2 align="center">
-   <img src="https://raw.githubusercontent.com/google-a2a/A2A/refs/heads/main/docs/assets/a2a-logo-black.svg" width="256" alt="A2A Logo"/>
-   </h2>
-   <h3 align="center">A Java library that helps run agentic applications as A2A servers following the <a href="https://a2a-protocol.org/">Agent2Agent (A2A) Protocol</a>.</h3>
+<h2 align="center">
+<img src="https://raw.githubusercontent.com/google-a2a/A2A/refs/heads/main/docs/assets/a2a-logo-black.svg" width="256" alt="A2A Logo"/>
+</h2>
+<h3 align="center">A Java library that helps run agentic applications as A2A servers following the <a href="https://a2a-protocol.org/">Agent2Agent (A2A) Protocol</a>.</h3>
 </html>
 
 A multi-module Maven library providing client and server support for A2A agent communication over JSON-RPC, gRPC, and REST transports.
@@ -32,10 +32,10 @@ Add the A2A Java SDK reference server for JSON-RPC to your Maven project:
 
 ```xml
 <dependency>
-    <groupId>org.a2aproject.sdk</groupId>
-    <artifactId>a2a-java-sdk-reference-jsonrpc</artifactId>
-    <!-- Use a released version from https://github.com/a2aproject/a2a-java/releases --> 
-    <version>${org.a2aproject.sdk.version}</version>
+	<groupId>org.a2aproject.sdk</groupId>
+	<artifactId>a2a-java-sdk-reference-jsonrpc</artifactId>
+	<!-- Use a released version from https://github.com/a2aproject/a2a-java/releases -->
+	<version>${org.a2aproject.sdk.version}</version>
 </dependency>
 ```
 

RELEASE.md

@@ -135,9 +135,9 @@ Pushing the tag triggers **two workflows**:
 2. Extracts version from tag name
 3. Generates release notes from commits since last release
 4. Creates GitHub release with:
-   - Auto-generated changelog
-   - Link to Maven Central artifacts
-   - Installation instructions
+- Auto-generated changelog
+- Link to Maven Central artifacts
+- Installation instructions
 
 ### 8. Verify Deployment