Add java-ci workflow for github actions

Updated the Java CI workflow to use JDK 21 and added steps for testing and coverage reporting.

Author: Captain-P-Goldfish

.github/workflows/maven.yml

@@ -0,0 +1,42 @@
+name: Java CI with Maven
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up JDK 21 (Amazon Corretto)
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'corretto'
+          java-version: '21'
+          cache: maven
+
+      - name: Verify Java
+        run: |
+          java -version
+          mvn -version
+
+      - name: Build and run tests
+        run: mvn -B clean package -DexcludedGroups=circle-ci-ignore
+
+      - name: Upload JaCoCo HTML report
+        uses: actions/upload-artifact@v4
+        with:
+          name: jacoco-report
+          path: target/site/jacoco-aggregate/
+
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@v6
+        with:
+          files: ./target/site/jacoco-aggregate/jacoco.xml
+          fail_ci_if_error: true
+          token: ${{ secrets.CODECOV_TOKEN }}