diff --git a/.gitea/workflows/demo.yaml b/.gitea/workflows/demo.yaml
index 771b56f..8506406 100644
--- a/.gitea/workflows/demo.yaml
+++ b/.gitea/workflows/demo.yaml
@@ -99,27 +99,35 @@ jobs:
           echo "Repository cloned successfully."
 
       # Install Maven manually
-      - name: Install Maven silently
-        run: |
-          MAVEN_VERSION="3.9.9"
-          MAVEN_DIR="/opt/maven"
-          wget -qO /tmp/apache-maven.tar.gz "https://downloads.apache.org/maven/maven-3/$MAVEN_VERSION/binaries/apache-maven-$MAVEN_VERSION-bin.tar.gz"
-          sudo mkdir -p "$MAVEN_DIR"
-          sudo tar -xzf /tmp/apache-maven.tar.gz --strip-components=1 -C "$MAVEN_DIR" >/dev/null
-          echo "MAVEN_HOME=$MAVEN_DIR" | sudo tee /etc/profile.d/maven.sh
-          echo "PATH=$MAVEN_DIR/bin:\$PATH" | sudo tee -a /etc/profile.d/maven.sh
-          export MAVEN_HOME="$MAVEN_DIR"
-          export PATH="$MAVEN_HOME/bin:$PATH"
-          mvn -v
+      - name: Checkout code
+        uses: actions/checkout@v4
 
-      # Cache Maven dependencies
-      - name: Cache Maven dependencies
-        uses: actions/cache@v3
+      # 1️⃣ Download OpenJDK 21 (example source URL)
+      - name: Download OpenJDK 21
+        run: |
+          download_url="https://download.oracle.com/java/21/latest/jdk-21_linux-x64_bin.tar.gz"
+          wget -O $RUNNER_TEMP/java_package.tar.gz $download_url
+
+      # 2️⃣ Setup Java from local JDK file
+      - name: Set up OpenJDK 21
+        uses: actions/setup-java@v5
         with:
-          path: ~/.m2/repository
-          key: maven-${{ runner.os }}-${{ hashFiles('**/pom.xml') }}
-          restore-keys: |
-            maven-${{ runner.os }}-
+          distribution: 'jdkfile'                     # Use locally downloaded JDK
+          jdkFile: ${{ runner.temp }}/java_package.tar.gz
+          java-version: '21'
+          architecture: x64
+          mvn-toolchain-vendor: 'Oracle'
+          cache: 'maven'                              # Enable Maven dependency caching
+
+      # 3️⃣ Verify Java installation
+      - name: Verify Java setup
+        run: |
+          java -version
+          echo "JAVA_HOME=$JAVA_HOME"
+
+      # 4️⃣ Build and test with Maven
+      - name: Build with Maven
+        run: mvn -B verify
 
       # Run backend tests and build
       - name: Test & build backend