diff --git a/.github/workflows/maven-verify.yml b/.github/workflows/maven-verify.yml
index 74e3dd69..c2f47dae 100644
--- a/.github/workflows/maven-verify.yml
+++ b/.github/workflows/maven-verify.yml
@@ -2,35 +2,45 @@ name: sdk-java Verify
 
 on:
   push:
-    branches:
-      - main
+    branches: [ main ]
   pull_request:
-    branches:
-      - main
+    branches: [ main ]
 
 jobs:
-  build:
+  lint:
+    name: Lint (Spotless + Checkstyle)
     runs-on: ubuntu-latest
+    steps:
+      - name: Checkout sdk-java
+        uses: actions/checkout@v4
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 17
+          cache: maven
+
+      - name: Spotless + Checkstyle (fail fast)
+        run: mvn -B -DskipTests spotless:check checkstyle:check
 
+  build:
+    name: Build & Verify
+    needs: lint
+    runs-on: ubuntu-latest
     steps:
-      # 1. Checkout this repo
       - name: Checkout sdk-java
         uses: actions/checkout@v4
 
-      # 2. Set up JDK 17 for both builds
       - name: Set up JDK 17
         uses: actions/setup-java@v4
         with:
           distribution: temurin
           java-version: 17
-          cache: 'maven'
+          cache: maven
 
-      # 3. Verify the main sdk-java project, excluding the two agentic modules
-      - name: Verify with Maven
+      - name: Verify with Maven (core)
         run: |
-          mvn -B -f pom.xml clean install verify -am
+          mvn -B -f pom.xml clean verify
 
-      # 4. Verify examples
-      - name: Verify Examples with Maven
-        run: |
-          mvn -B -f examples/pom.xml clean install verify
+      # TODO: run examples once we fix the close issue
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index fe76d40a..0b0ddfaf 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1,5 +1,134 @@
-## Hacking on Serverless Workflow Java SDK in Gitpod
+# Contributing
 
-If you have a web browser, you can get a fully pre-configured development environment in one click:
+Thanks for helping improve this project! This guide explains the local dev setup, the formatting/licensing workflow, testing, and how to propose changes.
 
-[![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/#https://github.com/serverlessworkflow/sdk-java)
\ No newline at end of file
+---
+
+## TL;DR (Fast path)
+
+1. **Install prerequisites:** JDK 17+, Maven 3.8+, Git.
+2. **Clone** the repo and create a branch: `git checkout -b my-fix`.
+3. **Build locally:** run `mvn clean install` from the repo root. Spotless will **apply formatting and license headers** during the build.
+4. **Before pushing:** run `mvn -DskipTests spotless:check checkstyle:check`.
+5. **Open a PR** with a clear title and description.
+
+---
+
+## Project Conventions
+
+### Java, Maven, and modules
+
+* This is a **multi-module Maven** project.
+* **Java 17** is the baseline.
+* Build with `mvn -B verify` (CI runs with `-DskipTests` selectively when needed).
+
+### Formatting and License Headers
+
+We use **Spotless** (Maven) to:
+
+* Format Java with **google-java-format**.
+* Insert/normalize **license headers** (the header content is defined **inline** in the parent POM’s `<licenseHeader>` configuration).
+
+> **Do not** hand-format files or hand-edit headers; let Spotless do it. Running `mvn clean install` locally will mutate sources to match the standard.
+
+### Checkstyle
+
+We keep **Checkstyle** to enforce additional rules. CI fails if formatting or style checks fail.
+
+---
+
+## Developer Setup
+
+### Prerequisites
+
+* **JDK 17+**
+* **Maven 3.8+**
+* **Git**
+* Optional IDE plugins:
+
+  * IntelliJ: *Google Java Format* plugin (for local editing experience). Spotless remains the source of truth.
+
+### Local build & formatting
+
+* Run `mvn clean install` from the repo root. During the build, Spotless **applies** formatting and license headers.
+* Before pushing, run `mvn -DskipTests spotless:check checkstyle:check` to ensure CI will pass.
+
+---
+
+## Testing
+
+* **Unit tests:** `mvn -q test` or `mvn verify`.
+* **Integration tests (if defined):** Use the dedicated Maven profile exposed by the module, e.g. `-Pintegration-tests`.
+* Prefer fast, deterministic tests. Avoid time-sensitive sleeps; use time abstractions or awaitility-style utilities.
+
+### Test Guidelines
+
+* Use clear, behavior-driven names: `methodName_shouldDoX_whenY`.
+* Keep one logical assertion per test (or one behavior per test).
+* Mock only external dependencies; don’t over-mock domain logic.
+* Make tests independent; no ordering assumptions.
+
+---
+
+## Commit & PR Guidelines
+
+### Branching
+
+* Use short, descriptive names: `fix/formatter`, `feat/http-call`, `docs/contributing`.
+
+### Commit messages
+
+* Keep messages clear and imperative: `Fix header resolution for child modules`.
+* Conventional Commits are welcome (`feat:`, `fix:`, `docs:`, `test:`, `refactor:`). Example: `feat: add A2A call task support`.
+
+### Pull Requests
+
+* Describe the **problem**, the **solution**, and any **trade-offs**.
+* Include before/after snippets or screenshots when relevant.
+* Link related issues.
+* Check the box:
+
+  * [ ] `mvn -DskipTests spotless:check checkstyle:check` passes locally
+  * [ ] Unit/integration tests updated
+  * [ ] Public API changes documented/Javadoc updated
+  * [ ] No unrelated formatting churn (Spotless should keep this minimal)
+
+---
+
+## Code Style & Design Notes
+
+* **Immutability first:** prefer `final` fields and defensive copies.
+* **Null-safety:** use `Objects.requireNonNull` at boundaries; consider `Optional` for truly optional returns (don’t use it for fields/params).
+* **Exceptions:** throw specific exceptions; include actionable messages; don’t swallow errors.
+* **Logging:** use SLF4J; no `System.out.println`; keep logs structured and at appropriate levels.
+* **APIs:** document with Javadoc; avoid breaking changes to public APIs unless necessary and called out in release notes.
+* **Generics & type-safety:** prefer precise types over `Object`; isolate unchecked casts.
+* **Performance:** avoid premature optimization; measure first; add micro-benchmarks (JMH) when optimizing hot paths.
+
+---
+
+## License Headers
+
+* The license header is defined **inline** in the parent POM under Spotless’ `<licenseHeader>`.
+* To update it, edit the parent POM and run `mvn spotless:apply` to propagate changes.
+
+---
+
+## CI
+
+* CI runs `spotless:check` and `checkstyle:check` to ensure consistent formatting and style.
+* Builds fail if formatting or headers drift. Run `mvn spotless:apply` locally to fix.
+
+---
+
+## Troubleshooting
+
+* **Spotless changed files during build?** That’s expected locally. Review `git status`, then stage and commit the updates.
+* **CI red on formatting?** Run `mvn spotless:apply` locally, commit, and push.
+* **Running only a submodule?** Prefer `mvn -pl <module> -am …` from the repo root so parent config (Spotless/Checkstyle) is applied consistently.
+
+---
+
+## Questions
+
+Open a discussion or issue on the repository. Thanks for contributing! 🎉
diff --git a/examples/events/pom.xml b/examples/events/pom.xml
index 439b3a11..e1461497 100644
--- a/examples/events/pom.xml
+++ b/examples/events/pom.xml
@@ -8,6 +8,12 @@
     </parent>
     <name>Serverless Workflow :: Examples :: Events</name>
     <artifactId>serverlessworkflow-examples-events</artifactId>
+
+    <properties>
+        <mainClass>events.EventExample</mainClass>
+    </properties>
+
+
     <dependencies>
         <dependency>
             <groupId>io.serverlessworkflow</groupId>
@@ -18,4 +24,12 @@
             <artifactId>slf4j-simple</artifactId>
         </dependency>
     </dependencies>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>exec-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
 </project>
\ No newline at end of file
diff --git a/examples/simpleGet/pom.xml b/examples/simpleGet/pom.xml
index 1a913363..f8d853b3 100644
--- a/examples/simpleGet/pom.xml
+++ b/examples/simpleGet/pom.xml
@@ -8,6 +8,11 @@
     </parent>
     <artifactId>serverlessworkflow-examples-simpleGet</artifactId>
     <name>Serverless Workflow :: Examples :: SimpleGet</name>
+
+    <properties>
+        <mainClass>io.serverlessworkflow.impl.BlockingExample</mainClass>
+    </properties>
+
     <dependencies>
         <dependency>
             <groupId>io.serverlessworkflow</groupId>
@@ -30,4 +35,15 @@
             <artifactId>slf4j-simple</artifactId>
         </dependency>
     </dependencies>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>exec-maven-plugin</artifactId>
+                <configuration>
+                    <mainClass>${mainClass}</mainClass>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
 </project>
\ No newline at end of file
diff --git a/experimental/lambda/src/main/java/io/serverlessworkflow/impl/executors/func/JavaForExecutorBuilder.java b/experimental/lambda/src/main/java/io/serverlessworkflow/impl/executors/func/JavaForExecutorBuilder.java
index fd11eae1..2f8ec073 100644
--- a/experimental/lambda/src/main/java/io/serverlessworkflow/impl/executors/func/JavaForExecutorBuilder.java
+++ b/experimental/lambda/src/main/java/io/serverlessworkflow/impl/executors/func/JavaForExecutorBuilder.java
@@ -13,7 +13,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package io.serverlessworkflow.impl.executors.func;
 
 import static io.serverlessworkflow.impl.executors.func.JavaFuncUtils.safeObject;
diff --git a/experimental/lambda/src/main/java/io/serverlessworkflow/impl/executors/func/JavaListenExecutorBuilder.java b/experimental/lambda/src/main/java/io/serverlessworkflow/impl/executors/func/JavaListenExecutorBuilder.java
index 3471cee3..295610bb 100644
--- a/experimental/lambda/src/main/java/io/serverlessworkflow/impl/executors/func/JavaListenExecutorBuilder.java
+++ b/experimental/lambda/src/main/java/io/serverlessworkflow/impl/executors/func/JavaListenExecutorBuilder.java
@@ -13,7 +13,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package io.serverlessworkflow.impl.executors.func;
 
 import static io.serverlessworkflow.impl.executors.func.JavaFuncUtils.predObject;
diff --git a/experimental/lambda/src/main/java/io/serverlessworkflow/impl/executors/func/JavaSwitchExecutorBuilder.java b/experimental/lambda/src/main/java/io/serverlessworkflow/impl/executors/func/JavaSwitchExecutorBuilder.java
index 2fe04b9c..b8163c4f 100644
--- a/experimental/lambda/src/main/java/io/serverlessworkflow/impl/executors/func/JavaSwitchExecutorBuilder.java
+++ b/experimental/lambda/src/main/java/io/serverlessworkflow/impl/executors/func/JavaSwitchExecutorBuilder.java
@@ -13,7 +13,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package io.serverlessworkflow.impl.executors.func;
 
 import static io.serverlessworkflow.impl.executors.func.JavaFuncUtils.predObject;
diff --git a/fluent/agentic/src/test/java/io/serverlessworkflow/fluent/agentic/WorkflowTests.java b/fluent/agentic/src/test/java/io/serverlessworkflow/fluent/agentic/WorkflowTests.java
index d38e863c..09cc12cc 100644
--- a/fluent/agentic/src/test/java/io/serverlessworkflow/fluent/agentic/WorkflowTests.java
+++ b/fluent/agentic/src/test/java/io/serverlessworkflow/fluent/agentic/WorkflowTests.java
@@ -13,7 +13,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package io.serverlessworkflow.fluent.agentic;
 
 import static io.serverlessworkflow.fluent.agentic.Agents.*;
diff --git a/generators/types/pom.xml b/generators/types/pom.xml
index 232009ea..215e390f 100644
--- a/generators/types/pom.xml
+++ b/generators/types/pom.xml
@@ -19,28 +19,4 @@
       </dependency>
         
     </dependencies>
-    <build>
-        <plugins>
-            <plugin>
-                <groupId>com.spotify.fmt</groupId>
-                <artifactId>fmt-maven-plugin</artifactId>
-                <configuration>
-                    <sourceDirectory>src/main/java</sourceDirectory>
-                    <testSourceDirectory>src/test/java</testSourceDirectory>
-                    <verbose>false</verbose>
-                    <filesNamePattern>.*\.java</filesNamePattern>
-                    <skip>false</skip>
-                    <skipSortingImports>false</skipSortingImports>
-                    <style>google</style>
-                </configuration>
-                <executions>
-                    <execution>
-                        <goals>
-                            <goal>format</goal>
-                        </goals>
-                    </execution>
-                </executions>
-            </plugin>
-        </plugins>
-    </build>
 </project>
\ No newline at end of file
diff --git a/impl/core/src/main/java/io/serverlessworkflow/impl/events/TypeEventRegistration.java b/impl/core/src/main/java/io/serverlessworkflow/impl/events/TypeEventRegistration.java
index 8fdf2388..c5828e72 100644
--- a/impl/core/src/main/java/io/serverlessworkflow/impl/events/TypeEventRegistration.java
+++ b/impl/core/src/main/java/io/serverlessworkflow/impl/events/TypeEventRegistration.java
@@ -13,7 +13,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package io.serverlessworkflow.impl.events;
 
 import io.cloudevents.CloudEvent;
diff --git a/impl/core/src/main/java/io/serverlessworkflow/impl/events/TypeEventRegistrationBuilder.java b/impl/core/src/main/java/io/serverlessworkflow/impl/events/TypeEventRegistrationBuilder.java
index bd504a76..39a2a699 100644
--- a/impl/core/src/main/java/io/serverlessworkflow/impl/events/TypeEventRegistrationBuilder.java
+++ b/impl/core/src/main/java/io/serverlessworkflow/impl/events/TypeEventRegistrationBuilder.java
@@ -13,7 +13,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package io.serverlessworkflow.impl.events;
 
 public record TypeEventRegistrationBuilder(String type, CloudEventPredicate cePredicate)
diff --git a/impl/core/src/main/java/io/serverlessworkflow/impl/expressions/RuntimeDescriptor.java b/impl/core/src/main/java/io/serverlessworkflow/impl/expressions/RuntimeDescriptor.java
index 66286632..e9893ed8 100644
--- a/impl/core/src/main/java/io/serverlessworkflow/impl/expressions/RuntimeDescriptor.java
+++ b/impl/core/src/main/java/io/serverlessworkflow/impl/expressions/RuntimeDescriptor.java
@@ -13,7 +13,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package io.serverlessworkflow.impl.expressions;
 
 import java.util.Map;
diff --git a/impl/core/src/main/java/io/serverlessworkflow/impl/lifecycle/TaskCompletedEvent.java b/impl/core/src/main/java/io/serverlessworkflow/impl/lifecycle/TaskCompletedEvent.java
index e7ab1084..a4e36156 100644
--- a/impl/core/src/main/java/io/serverlessworkflow/impl/lifecycle/TaskCompletedEvent.java
+++ b/impl/core/src/main/java/io/serverlessworkflow/impl/lifecycle/TaskCompletedEvent.java
@@ -13,7 +13,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
 package io.serverlessworkflow.impl.lifecycle;
 
 import io.serverlessworkflow.impl.TaskContext;
diff --git a/pom.xml b/pom.xml
index 79d7182f..b9fa70bd 100644
--- a/pom.xml
+++ b/pom.xml
@@ -58,16 +58,17 @@
         <!-- Plugin versions, please keep in alphabetical order -->
         <version.buildnumber.plugin>3.2.1</version.buildnumber.plugin>
         <version.checkstyle.plugin>3.6.0</version.checkstyle.plugin>
+        <version.com.diffplug.spotless>2.43.0</version.com.diffplug.spotless>
         <version.compiler.plugin>3.14.0</version.compiler.plugin>
         <version.deploy.plugin>3.1.4</version.deploy.plugin>
         <version.enforcer.plugin>3.6.1</version.enforcer.plugin>
         <version.failsafe.plugin>3.5.3</version.failsafe.plugin>
-        <version.fmt-maven-plugin>2.27</version.fmt-maven-plugin>
         <version.gpg.plugin>3.2.8</version.gpg.plugin>
         <version.jar.plugin>3.4.2</version.jar.plugin>
         <version.jdk>${java.version}</version.jdk>
         <version.jsonschema2pojo-maven-plugin>1.2.2</version.jsonschema2pojo-maven-plugin>
         <version.javadoc.plugin>3.11.3</version.javadoc.plugin>
+        <version.org.codehaus.mojo>3.5.1</version.org.codehaus.mojo>
         <version.release.plugin>3.1.1</version.release.plugin>
         <version.source.plugin>3.3.1</version.source.plugin>
         <version.surefire.plugin>3.5.3</version.surefire.plugin>
@@ -93,28 +94,12 @@
 
         <!-- Checkstyle props -->
         <checkstyle.failOnViolation>true</checkstyle.failOnViolation>
-        <checkstyle.header.template><![CDATA[
-^\/\*$\n^
-\* Copyright \d\d\d\d-Present The Serverless Workflow Specification Authors$\n^
-\*$\n^
-\* Licensed under the Apache License, Version 2\.0 \(the &quot;License&quot;\);$\n^
-\* you may not use this file except in compliance with the License\.$\n^
-\* You may obtain a copy of the License at$\n^
-\*$\n^
-\* http:\/\/www\.apache\.org\/licenses\/LICENSE-2\.0$\n^
-\*$\n^
-\* Unless required by applicable law or agreed to in writing, software$\n^
-\* distributed under the License is distributed on an &quot;AS IS&quot; BASIS,$\n^
-\* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied\.$\n^
-\* See the License for the specific language governing permissions and$\n^
-\* limitations under the License\.$\n^
-\*\/$
-]]>
-        </checkstyle.header.template>
         <checkstyle.header.extensions>java</checkstyle.header.extensions>
         <checkstyle.logViolationsToConsole>true</checkstyle.logViolationsToConsole>
 
         <integration-tests.includes>**/*IT.java</integration-tests.includes>
+
+        <rootDir>${maven.multiModuleProjectDirectory}</rootDir>
     </properties>
 
     <dependencyManagement>
@@ -282,10 +267,6 @@
                 <configuration>
                     <checkstyleRules>
                         <module name="Checker">
-                            <module name="RegexpHeader">
-                                <property name="header" value="${checkstyle.header.template}" />
-                                <property name="fileExtensions" value="${checkstyle.header.extensions}" />
-                            </module>
                             <module name="TreeWalker">
                                 <module name="RegexpSinglelineJava">
                                     <property name="format" value="@author" />
@@ -317,26 +298,53 @@
                 </executions>
             </plugin>
             <plugin>
-                <groupId>com.spotify.fmt</groupId>
-                <artifactId>fmt-maven-plugin</artifactId>
+                <groupId>com.diffplug.spotless</groupId>
+                <artifactId>spotless-maven-plugin</artifactId>
                 <configuration>
-                    <sourceDirectory>src/main/java</sourceDirectory>
-                    <testSourceDirectory>src/test/java</testSourceDirectory>
-                    <verbose>false</verbose>
-                    <filesNamePattern>.*\.java</filesNamePattern>
-                    <skip>false</skip>
-                    <skipSortingImports>false</skipSortingImports>
-                    <style>google</style>
+                    <java>
+                        <!-- formatter -->
+                        <googleJavaFormat version="1.17.0" />
+                        <!-- add/normalize headers -->
+                        <licenseHeader>
+                            <content>
+                                <![CDATA[
+/*
+ * Copyright 2020-Present The Serverless Workflow Specification Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+        ]]>
+                            </content>
+                        </licenseHeader>
+                    </java>
                 </configuration>
                 <executions>
                     <execution>
+                        <id>spotless-apply-on-validate</id>
+                        <phase>validate</phase>
+                        <goals>
+                            <goal>apply</goal>
+                        </goals>
+                    </execution>
+                    <execution>
+                        <id>spotless-check-on-verify</id>
+                        <phase>verify</phase>
                         <goals>
-                            <goal>format</goal>
+                            <goal>check</goal>
                         </goals>
                     </execution>
                 </executions>
             </plugin>
-
         </plugins>
 
         <pluginManagement>
@@ -470,9 +478,9 @@
                     <version>${version.checkstyle.plugin}</version>
                 </plugin>
                 <plugin>
-                    <groupId>com.spotify.fmt</groupId>
-                    <artifactId>fmt-maven-plugin</artifactId>
-                    <version>${version.fmt-maven-plugin}</version>
+                    <groupId>com.diffplug.spotless</groupId>
+                    <artifactId>spotless-maven-plugin</artifactId>
+                    <version>${version.com.diffplug.spotless}</version>
                 </plugin>
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
@@ -511,6 +519,18 @@
                         <failOnError>false</failOnError>
                     </configuration>
                 </plugin>
+                <plugin>
+                    <groupId>org.codehaus.mojo</groupId>
+                    <artifactId>exec-maven-plugin</artifactId>
+                    <version>${version.org.codehaus.mojo}</version>
+                    <executions>
+                        <execution>
+                            <goals>
+                                <goal>java</goal>
+                            </goals>
+                        </execution>
+                    </executions>
+                </plugin>
             </plugins>
         </pluginManagement>
     </build>