set headless for servers without X11.

pom.xml

@@ -200,49 +200,16 @@
             <target>1.6</target>
           </configuration>
         </plugin>
-        <!-- TODO: create mvn:site -->
-        <!--<plugin>-->
-        <!--<groupId>org.apache.maven.plugins</groupId>-->
-        <!--<artifactId>maven-site-plugin</artifactId>-->
-        <!--<version>3.0</version>-->
-        <!--<configuration>-->
-        <!--<locales>en</locales>-->
-        <!--<inputEncoding>UTF-8</inputEncoding>-->
-        <!--<outputEncoding>UTF-8</outputEncoding>-->
-        <!--<reportPlugins>-->
-        <!--<reportPlugin>-->
-        <!--<groupId>org.apache.maven.plugins</groupId>-->
-        <!--<artifactId>maven-project-info-reports-plugin</artifactId>-->
-        <!--<configuration>-->
-        <!--<dependencyDetailsEnabled>false</dependencyDetailsEnabled>-->
-        <!--<dependencyLocationsEnabled>false</dependencyLocationsEnabled>-->
-        <!--</configuration>-->
-        <!--<reportSets>-->
-        <!--<reportSet>-->
-        <!--<reports>-->
-        <!--<report>index</report>-->
-        <!--<report>summary</report>-->
-        <!--<report>dependency-management</report>-->
-        <!--<report>issue-tracking</report>-->
-        <!--<report>help</report>-->
-        <!--<report>modules</report>-->
-        <!--<report>dependencies</report>-->
-        <!--<report>plugins</report>-->
-        <!--<report>cim</report>-->
-        <!--<report>license</report>-->
-        <!--<report>mailing-list</report>-->
-        <!--<report>project-team</report>-->
-        <!--<report>scm</report>-->
-        <!--<report>dependencies</report>-->
-        <!--<report>distribution-management</report>-->
-        <!--</reports>-->
-        <!--</reportSet>-->
-        <!--</reportSets>-->
-        <!--</reportPlugin>-->
-        <!--</reportPlugins>-->
-        <!--</configuration>-->
-        <!--</plugin>-->
-
+        <plugin>
+          <groupId>org.apache.maven.plugins</groupId>
+          <artifactId>maven-surefire-plugin</artifactId>
+          <version>2.16</version>
+          <configuration>
+            <systemProperties>
+              <java.awt.headless>true</java.awt.headless>
+            </systemProperties>
+          </configuration>
+        </plugin>
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-plugin-plugin</artifactId>