Add Java build on PRs (#7)

* Add Java build on PRs

* Fix cwd

.github/workflows/java.yml

@@ -0,0 +1,25 @@
+# This workflow will build a Java project with Maven, and cache/restore any dependencies to improve the workflow execution time
+name: Java CI
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+    - name: Set up JDK 17
+      uses: actions/setup-java@v3
+      with:
+        java-version: '17'
+        distribution: 'temurin'
+        cache: maven
+    - name: Build with Maven
+      working-directory: ./Java
+      run: mvn -B package