Re-use built artifacts (compiled classes) to save some build job runtime

Do no longer clean before deployment, just re-use the pre-built class files, skip compiling again

Author: travkin79

.github/workflows/ci.yml

@@ -46,6 +46,14 @@ jobs:
     - name: Build with Maven
       run: mvn -B clean verify --file pom.xml
 
+    - name: Upload compiled classes
+      if: matrix.os == 'ubuntu-latest'
+      uses: actions/upload-artifact@v4
+      with:
+        name: build-classes
+        path: '**/target/classes'
+        retention-days: 1
+
     # Optional: Uploads the full dependency graph to GitHub to improve the quality of Dependabot alerts this repository can receive
     #- name: Update dependency graph
     #  uses: advanced-security/maven-dependency-submission-action@571e99aab1055c2e71a1e2309b9691de18d6b7d6
@@ -69,7 +77,12 @@ jobs:
         distribution: 'temurin'
         cache: maven
 
+    - name: Download compiled classes
+      uses: actions/download-artifact@v4
+      with:
+        name: build-classes
+
     - name: Deploy to GitHub Maven Packages
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-      run: mvn -B clean -Pdeploy-github -DskipTests deploy
+      run: mvn -B -Pdeploy-github -Dmaven.compiler.skip=true -Dmaven.test.skip=true deploy