diff --git a/meecrowave-doc/src/main/java/org/apache/meecrowave/doc/generator/GradleConfiguration.java b/meecrowave-doc/src/main/java/org/apache/meecrowave/doc/generator/GradleConfiguration.java
index c195f75..2ff58a4 100644
--- a/meecrowave-doc/src/main/java/org/apache/meecrowave/doc/generator/GradleConfiguration.java
+++ b/meecrowave-doc/src/main/java/org/apache/meecrowave/doc/generator/GradleConfiguration.java
@@ -19,6 +19,7 @@
 package org.apache.meecrowave.doc.generator;
 
 import static java.util.Comparator.comparing;
+import static java.util.Optional.ofNullable;
 import static java.util.stream.Collectors.joining;
 
 import java.lang.reflect.Field;
@@ -43,7 +44,7 @@
     private String toLine(final Field opt) {
         opt.setAccessible(true);
         try {
-            return '|' + opt.getName() + '|' + opt.get(defaults) + '|' + findDescription(opt.getName());
+            return '|' + opt.getName() + '|' + ofNullable(opt.get(defaults)).orElse("-") + '|' + findDescription(opt.getName());
         } catch (final IllegalAccessException e) {
             throw new IllegalStateException(e);
         }
diff --git a/meecrowave-doc/src/main/jbake/templates/footer.gsp b/meecrowave-doc/src/main/jbake/templates/footer.gsp
index 9f83417..a189dbc 100755
--- a/meecrowave-doc/src/main/jbake/templates/footer.gsp
+++ b/meecrowave-doc/src/main/jbake/templates/footer.gsp
@@ -19,7 +19,11 @@
     <script type="text/javascript" src="/meecrowave/assets/plugins/jquery-1.12.3.min.js"></script>
     <script type="text/javascript" src="/meecrowave/assets/plugins/bootstrap/js/bootstrap.min.js"></script>
     <script type="text/javascript" src="/meecrowave/assets/plugins/jquery-match-height/jquery.matchHeight-min.js"></script>
-    <script type="text/javascript" src="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.9.0/highlight.min.js"></script>
+    <script src="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.15.6/highlight.min.js" integrity="sha256-aYTdUrn6Ow1DDgh5JTc3aDGnnju48y/1c8s1dgkYPQ8=" crossorigin="anonymous"></script>
+    <script src="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.15.6/languages/java.min.js" integrity="sha256-21Z1xKC/FsaqN9z9jIER9xiX4XbV5buFEVdkZvsfBIc=" crossorigin="anonymous"></script>
+    <script src="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.15.6/languages/groovy.min.js" integrity="sha256-0B+Ps1zCncLC5JIOQ+MtIhI/UhbJkYbxWsJowD3c+tk=" crossorigin="anonymous"></script>
+    <script src="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.15.6/languages/shell.min.js" integrity="sha256-nwOM3xEc6CFfrPNDN1upX+5ynjWKAXsg+bW63SSzte0=" crossorigin="anonymous"></script>
+    <script src="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.15.6/languages/bash.min.js" integrity="sha256-zXrlim8wsIvcEFjsD3THiAfTvtPZifqx8q0rxegiWQc=" crossorigin="anonymous"></script>
     <script type="text/javascript" src="/meecrowave/assets/js/main.js?version=1"></script>
 
 </body>
diff --git a/meecrowave-doc/src/main/jbake/templates/header.gsp b/meecrowave-doc/src/main/jbake/templates/header.gsp
index 12fa65b..c712c01 100755
--- a/meecrowave-doc/src/main/jbake/templates/header.gsp
+++ b/meecrowave-doc/src/main/jbake/templates/header.gsp
@@ -18,7 +18,7 @@
     <link rel="stylesheet" href="/meecrowave/assets/plugins/font-awesome/css/font-awesome.min.css">
     <link rel="stylesheet" href="/meecrowave/assets/plugins/elegant_font/css/style.css?version=1">
     <!-- highlighting -->
-    <link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.9.0/styles/idea.min.css">
+    <link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.15.6/styles/idea.min.css" integrity="sha256-rYB1c4yTU5UJB//rod7DtBo1JM6HAme/9Vd+VesFG2U=" crossorigin="anonymous" />
 
     <!-- Theme CSS -->
     <link id="theme-style" rel="stylesheet" href="/meecrowave/assets/css/styles.css">