using java 1.7 for compilation (for ClassLoader.close() called in DefaultPluginManager)

pom.xml

@@ -32,6 +32,7 @@
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <java.version>1.7</java.version>
     </properties>
 
     <build>
@@ -41,8 +42,8 @@
                 <artifactId>maven-compiler-plugin</artifactId>
                 <version>2.3.2</version>
                 <configuration>
-                    <source>1.6</source>
+                    <source>${java.version}</source>
-                    <target>1.6</target>
+                    <target>${java.version}</target>
                     <optimize>true</optimize>
                 </configuration>
             </plugin>