Fix compilation and add github workflows

.github/workflows/build.yml

@@ -0,0 +1,28 @@
+name: Build
+on:
+  push:
+    branches: 
+      - main
+      - master
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+      with:
+        fetch-depth: 0
+    - name: Cache local Maven repository
+      uses: actions/cache@v3
+      with:
+        path: ~/.m2/repository
+        key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
+        restore-keys: ${{ runner.os }}-maven-
+    - name: Set up JDK Corretto 8
+      uses: actions/setup-java@v3
+      with:
+        distribution: 'corretto'
+        java-version: '8'
+        architecture: x64
+    - name: Maven Build
+      run: mvn clean install
+

.github/workflows/pull-request.yml

@@ -0,0 +1,33 @@
+name: Pull Request
+
+on:
+  pull_request:
+    branches: 
+      - main
+      - master
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+jobs:
+  build:        
+    runs-on: ${{ matrix.os }}-latest
+    strategy:
+      matrix:
+        os: [ubuntu, windows]
+    steps:
+    - uses: actions/checkout@v3
+      with:
+        fetch-depth: 0
+    - name: Cache local Maven repository
+      uses: actions/cache@v3
+      with:
+        path: ~/.m2/repository
+        key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
+        restore-keys: ${{ runner.os }}-maven-
+    - name: Set up JDK Corretto 8
+      uses: actions/setup-java@v3
+      with:
+        distribution: 'corretto'
+        java-version: 8
+    - name: Maven Build
+      run: mvn clean install

odata2-jpa-processor/jpa-core/pom.xml

@@ -70,8 +70,8 @@
                           <artifactId>maven-compiler-plugin</artifactId>
                           <version>2.3.2</version>
                           <configuration>
-                            <source>1.6</source>
-                            <target>1.6</target>
+                            <source>1.8</source>
+                            <target>1.8</target>
                           </configuration>
                         </plugin>
                 </plugins>