diff --git a/asciidoctorj-core/src/main/java/org/asciidoctor/internal/JRubyAsciidoctor.java b/asciidoctorj-core/src/main/java/org/asciidoctor/internal/JRubyAsciidoctor.java
index b908dadbd..e6947c488 100644
--- a/asciidoctorj-core/src/main/java/org/asciidoctor/internal/JRubyAsciidoctor.java
+++ b/asciidoctorj-core/src/main/java/org/asciidoctor/internal/JRubyAsciidoctor.java
@@ -26,9 +26,17 @@
 import org.jruby.exceptions.RaiseException;
 import org.jruby.javasupport.JavaEmbedUtils;
 
-import java.io.*;
-import java.util.*;
-import java.util.logging.Level;
+import java.io.File;
+import java.io.IOException;
+import java.io.Reader;
+import java.io.Writer;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
 import java.util.logging.Logger;
 
 public class JRubyAsciidoctor implements Asciidoctor {
@@ -299,16 +307,13 @@ public String render(String content, Map<String, Object> options) {
 
         RubyHash rubyHash = RubyHashUtil.convertMapToRubyHashWithSymbols(rubyRuntime, options);
 
-        ClassLoader oldTCCL = Thread.currentThread().getContextClassLoader();
         try {
-            Thread.currentThread().setContextClassLoader(rubyRuntime.getJRubyClassLoader());
             Object object = this.asciidoctorModule.convert(content, rubyHash);
             return returnExpectedValue(object);
         } catch(RaiseException e) {
             logger.severe(e.getException().getClass().getCanonicalName());
             throw new AsciidoctorCoreException(e);
         } finally {
-            Thread.currentThread().setContextClassLoader(oldTCCL);
             // we restore current directory to its original value.
             rubyRuntime.setCurrentDirectory(currentDirectory);
         }
@@ -332,16 +337,13 @@ public String renderFile(File filename, Map<String, Object> options) {
 
         RubyHash rubyHash = RubyHashUtil.convertMapToRubyHashWithSymbols(rubyRuntime, options);
 
-        ClassLoader oldTCCL = Thread.currentThread().getContextClassLoader();
         try {
-            Thread.currentThread().setContextClassLoader(rubyRuntime.getJRubyClassLoader());
             Object object = this.asciidoctorModule.convertFile(filename.getAbsolutePath(), rubyHash);
             return returnExpectedValue(object);
         } catch(RaiseException e) {
             logger.severe(e.getMessage());
             throw new AsciidoctorCoreException(e);
         } finally {
-            Thread.currentThread().setContextClassLoader(oldTCCL);
             // we restore current directory to its original value.
             rubyRuntime.setCurrentDirectory(currentDirectory);
         }
diff --git a/asciidoctorj-diagram/gradle.properties b/asciidoctorj-diagram/gradle.properties
index 402172dfd..b0cf46021 100644
--- a/asciidoctorj-diagram/gradle.properties
+++ b/asciidoctorj-diagram/gradle.properties
@@ -1,4 +1,4 @@
 properName=AsciidoctorJ Diagram
 description=AsciidoctorJ Diagram bundles the Asciidoctor Diagram RubyGem (asciidoctor-diagram) so it can be loaded into the JVM using JRuby.
-version=1.5.5
+version=1.5.4
 gem_name=asciidoctor-diagram
diff --git a/build.gradle b/build.gradle
index 35a867f01..7661a85a4 100644
--- a/build.gradle
+++ b/build.gradle
@@ -45,7 +45,7 @@ ext {
   xmlMatchersVersion = '1.0-RC1'
 
   // gem versions
-  asciidoctorGemVersion = project.hasProperty('asciidoctorGemVersion') ? project.asciidoctorGemVersion : '1.5.6'
+  asciidoctorGemVersion = project.hasProperty('asciidoctorGemVersion') ? project.asciidoctorGemVersion : '1.5.6.1'
   asciidoctorEpub3GemVersion = project(':asciidoctorj-epub3').version.replace('-', '.')
 
   asciidoctorDiagramGemVersion = project(':asciidoctorj-diagram').version.replace('-', '.')