-upgrade java.testversion so that support lambda in test cases

Author: BalloonWen

pom.xml

@@ -59,7 +59,7 @@
     </distributionManagement>
     <properties>
         <java.version>1.8</java.version>
-        <java.testversion>1.7</java.testversion>
+        <java.testversion>1.8</java.testversion>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <version.jackson>2.9.9</version.jackson>
         <version.slf4j>1.7.25</version.slf4j>