Add japicmp
diff --git a/pom.xml b/pom.xml
index 636e3c5..8145ca9 100644
--- a/pom.xml
+++ b/pom.xml
@@ -211,6 +211,8 @@
     <commons.osgi.export>!org.apache.commons.fileupload.util.mime,org.apache.commons.*;version=${project.version};-noimport:=true</commons.osgi.export>
     <commons.osgi.import>!javax.portlet,*</commons.osgi.import>
     <commons.osgi.dynamicImport>javax.portlet</commons.osgi.dynamicImport>
+    <commons.japicmp.version>0.13.0</commons.japicmp.version>
+    <japicmp.skip>false</japicmp.skip>
 
     <!-- Commons Release Plugin -->
     <commons.release.version>1.4</commons.release.version>
@@ -270,6 +272,24 @@
     </plugins>
     <pluginManagement>
       <plugins>
+        <plugin>
+          <groupId>org.apache.rat</groupId>
+          <artifactId>apache-rat-plugin</artifactId>
+          <configuration>
+            <excludes>
+              <exclude>site-content/**</exclude>
+              <exclude>src/site/resources/download_lang.cgi</exclude>
+              <exclude>src/checkstyle/license-header.txt</exclude>
+            </excludes>
+          </configuration>
+        </plugin><!-- override skip property of parent pom -->
+        <plugin>
+          <groupId>com.github.siom79.japicmp</groupId>
+          <artifactId>japicmp-maven-plugin</artifactId>
+          <configuration>
+            <skip>false</skip>
+          </configuration>
+        </plugin>
         <!--This plugin's configuration is used to store Eclipse m2e settings only. It has no influence on the Maven build itself.-->
         <plugin>
           <groupId>org.eclipse.m2e</groupId>