diff --git a/.travis.yml b/.travis.yml
index 98e9bf872..c5c16d392 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,8 +7,6 @@ matrix:
     - jdk: oraclejdk8
     - jdk: oraclejdk7
     - jdk: openjdk7
-  allow_failures:
-    - jdk: oraclejdk9
 before_script: unset GEM_PATH GEM_HOME JRUBY_OPTS
 before_install:
   - sudo hostname "$(hostname | cut -c1-63)"
diff --git a/asciidoctorj-core/src/test/java/org/asciidoctor/extension/WhenRubyExtensionGroupIsRegistered.java b/asciidoctorj-core/src/test/java/org/asciidoctor/extension/WhenRubyExtensionGroupIsRegistered.java
index ac4e13c63..a44f13cef 100644
--- a/asciidoctorj-core/src/test/java/org/asciidoctor/extension/WhenRubyExtensionGroupIsRegistered.java
+++ b/asciidoctorj-core/src/test/java/org/asciidoctor/extension/WhenRubyExtensionGroupIsRegistered.java
@@ -29,7 +29,7 @@ public class WhenRubyExtensionGroupIsRegistered {
     public void ruby_extension_should_be_registered() {
         
         this.asciidoctor.createGroup()
-            .loadRubyClass(Class.class.getResourceAsStream("/YellRubyBlock.rb")).rubyBlock("rubyyell", "YellRubyBlock")
+            .loadRubyClass(getClass().getResourceAsStream("/YellRubyBlock.rb")).rubyBlock("rubyyell", "YellRubyBlock")
             .register();
 
         String content = asciidoctor.renderFile(
@@ -47,7 +47,7 @@ public void ruby_extension_should_be_registered() {
     public void ruby_extension_should_be_unregistered() {
 
         ExtensionGroup extensionGroup = this.asciidoctor.createGroup()
-            .loadRubyClass(Class.class.getResourceAsStream("/YellRubyBlock.rb"))
+            .loadRubyClass(getClass().getResourceAsStream("/YellRubyBlock.rb"))
             .rubyBlock("rubyyell", "YellRubyBlock");
 
         {
diff --git a/asciidoctorj-core/src/test/java/org/asciidoctor/extension/WhenRubyExtensionIsRegistered.java b/asciidoctorj-core/src/test/java/org/asciidoctor/extension/WhenRubyExtensionIsRegistered.java
index c7240ec28..6e756d713 100644
--- a/asciidoctorj-core/src/test/java/org/asciidoctor/extension/WhenRubyExtensionIsRegistered.java
+++ b/asciidoctorj-core/src/test/java/org/asciidoctor/extension/WhenRubyExtensionIsRegistered.java
@@ -29,7 +29,7 @@ public class WhenRubyExtensionIsRegistered {
     public void ruby_extension_should_be_registered() {
         
         RubyExtensionRegistry rubyExtensionRegistry = this.asciidoctor.rubyExtensionRegistry();
-        rubyExtensionRegistry.loadClass(Class.class.getResourceAsStream("/YellRubyBlock.rb")).block("rubyyell", "YellRubyBlock");
+        rubyExtensionRegistry.loadClass(getClass().getResourceAsStream("/YellRubyBlock.rb")).block("rubyyell", "YellRubyBlock");
 
         String content = asciidoctor.renderFile(
                 classpath.getResource("sample-with-ruby-yell-block.ad"),
diff --git a/build.gradle b/build.gradle
index d2f0d2d37..e2a71db2e 100644
--- a/build.gradle
+++ b/build.gradle
@@ -57,7 +57,7 @@ ext {
   coderayGemVersion = '1.1.0'
 
   codenarcVersion = '0.24.1'
-  groovyVersion = '2.4.7'
+  groovyVersion = '2.4.13'
   erubisGemVersion = '2.7.0'
   hamlGemVersion = '4.0.5'
   openUriCachedGemVersion = '0.0.5'