use Java 8
diff --git a/pom.xml b/pom.xml
index 036bb85..05b4031 100644
--- a/pom.xml
+++ b/pom.xml
@@ -38,6 +38,10 @@
         <url>https://gitbox.apache.org/repos/asf?p=sling-org-apache-sling-validation-test-services.git</url>
     </scm>
 
+    <properties>
+        <sling.java.version>8</sling.java.version>
+    </properties>
+
     <build>
         <plugins>
             <plugin>