Add github actions for code format/style check.

.github/actions/checkstyle/action.yml

@@ -0,0 +1,36 @@
+name: "CheckSyle Validation"
+description: "Check some code style rules with Maven"
+
+runs:
+  using: "composite"
+  steps:
+
+  - name: Check Code Style
+    id: checkstyle
+    shell: bash
+    run: mvn -B checkstyle:checkstyle
+
+  - name: Add comment
+    if: failure()
+    uses: marocchino/sticky-pull-request-comment@v2
+    with:
+      header: Checkstyle Validation Failed
+      message: |
+        :x: **Checkstyle Validation Failed !** [(more details)](${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }})
+
+        Ensure your code build locally using: 
+        ```
+        mvn clean install
+        ```
+        Or just validate checkstyle rules with : 
+        ```
+        mvn checkstyle:checkstyle
+        ```
+        See also [How configure your IDE](https://github.com/eclipse/leshan/wiki/Code-&-design-guidelines#configure-your-ide).
+
+  - name: Delete comment
+    if: success()
+    uses: marocchino/sticky-pull-request-comment@v2
+    with:
+      header: Checkstyle Validation Failed
+      delete: true

.github/actions/formatter/action.yml

@@ -0,0 +1,40 @@
+name: "Check code Format"
+description: "Check code is well formatted with Maven"
+
+runs:
+  using: "composite"
+  steps:
+
+  - name: Check Code Format
+    id: formatter
+    shell: bash
+    run: mvn -B formatter:validate
+
+  - name: Add comment
+    if: failure()
+    uses: marocchino/sticky-pull-request-comment@v2
+    with:
+      header: Code Formatter Validation Failed
+      message: |
+        :x: **Code is not well-formatted !** [(more details)](${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }})
+
+        Ensure your code build locally using: 
+        ```
+        mvn clean install
+        ```
+        Or just validate code format with : 
+        ```
+        mvn formatter:validate
+        ```
+        You can format the code with : 
+        ```
+        mvn formatter:format
+        ```
+        See also [How configure your IDE](https://github.com/eclipse/leshan/wiki/Code-&-design-guidelines#configure-your-ide).
+
+  - name: Delete comment
+    if: success()
+    uses: marocchino/sticky-pull-request-comment@v2
+    with:
+      header: Code Formatter Validation Failed
+      delete: true

.github/actions/javadoc/action.yml

@@ -8,7 +8,7 @@ runs:
   - name: Generate Javadoc
     id: javadoc
     shell: bash
-    run: mvn -B javadoc:javadoc
+    run: mvn -B javadoc:javadoc-no-fork
 
   - name: Add comment
     if: failure()

.github/workflows/main.yml

@@ -30,11 +30,21 @@ jobs:
     - name: Check No Merge Commit
       uses: ./.github/actions/no_merge
 
+    - name: Code Format Check
+      if: always()
+      id: formatter
+      uses: ./.github/actions/formatter
+
     - name: Build
       if: always()
       id: build
       uses: ./.github/actions/build
 
+    - name: Code Style Check
+      if: always()
+      id: checkstyle
+      uses: ./.github/actions/checkstyle
+
     - name: Check Android API Compliance
       if: ${{ always() && steps.build.conclusion == 'success' }}
       uses: ./.github/actions/android-check

pom.xml

@@ -131,6 +131,8 @@ Contributors:
                 <maven.javadoc.skip>true</maven.javadoc.skip>
                 <animal.sniffer.skip>true</animal.sniffer.skip>
                 <revapi.skip>true</revapi.skip>
+                <formatter.skip>true</formatter.skip>
+                <checkstyle.skip>true</checkstyle.skip>
             </properties>
         </profile>
     </profiles>