diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
index b00e004c..301a8418 100644
--- a/CHANGELOG.adoc
+++ b/CHANGELOG.adoc
@@ -13,6 +13,10 @@ For a detailed view of what has changed, refer to the {uri-repo}/commits/master[
 
 == Unreleased
 
+Bug Fixes::
+
+* When creating an AsciidoctorJ instance with classloader parameter, extensions are not discovered (@ahus1) (#942)
+
 == 2.4.0 (2020-07-19)
 
 Improvement::
diff --git a/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/converter/internal/ConverterRegistryExecutor.java b/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/converter/internal/ConverterRegistryExecutor.java
index 6e9b93c8..fcc9b20f 100644
--- a/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/converter/internal/ConverterRegistryExecutor.java
+++ b/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/converter/internal/ConverterRegistryExecutor.java
@@ -14,8 +14,12 @@ public ConverterRegistryExecutor(AsciidoctorJRuby asciidoctor) {
     }
 
     public void registerAllConverters() {
+        registerAllConverters(Thread.currentThread().getContextClassLoader());
+    }
+
+    public void registerAllConverters(ClassLoader classloader) {
         ServiceLoader<ConverterRegistry> converterRegistryServiceLoader = ServiceLoader
-                .load(ConverterRegistry.class);
+                .load(ConverterRegistry.class, classloader);
 
         for (ConverterRegistry converterRegistry : converterRegistryServiceLoader) {
             converterRegistry.register(asciidoctor);
diff --git a/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/extension/internal/ExtensionRegistryExecutor.java b/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/extension/internal/ExtensionRegistryExecutor.java
index 5141029f..33cde92f 100644
--- a/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/extension/internal/ExtensionRegistryExecutor.java
+++ b/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/extension/internal/ExtensionRegistryExecutor.java
@@ -14,9 +14,13 @@ public ExtensionRegistryExecutor(AsciidoctorJRuby asciidoctor) {
     }
 
     public void registerAllExtensions() {
+        registerAllExtensions(Thread.currentThread().getContextClassLoader());
+    }
+
+    public void registerAllExtensions(ClassLoader classloader) {
         ServiceLoader<ExtensionRegistry> extensionRegistryServiceLoader = ServiceLoader
-                .load(ExtensionRegistry.class);
-        
+                .load(ExtensionRegistry.class, classloader);
+
         for (ExtensionRegistry extensionRegistry : extensionRegistryServiceLoader) {
             extensionRegistry.register(asciidoctor);
         }
diff --git a/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/internal/JRubyAsciidoctor.java b/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/internal/JRubyAsciidoctor.java
index eff33ed1..8955fff2 100644
--- a/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/internal/JRubyAsciidoctor.java
+++ b/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/internal/JRubyAsciidoctor.java
@@ -74,11 +74,15 @@ public static JRubyAsciidoctor create(List<String> loadPaths) {
     }
 
     public static JRubyAsciidoctor create(ClassLoader classloader) {
-        return processRegistrations(createJRubyAsciidoctorInstance(null, new ArrayList<>(), classloader));
+        return processRegistrations(
+                createJRubyAsciidoctorInstance(null, new ArrayList<>(), classloader),
+                classloader);
     }
 
     public static JRubyAsciidoctor create(ClassLoader classloader, String gemPath) {
-        return processRegistrations(createJRubyAsciidoctorInstance(Collections.singletonMap(GEM_PATH, gemPath), new ArrayList<>(), classloader));
+        return processRegistrations(
+                createJRubyAsciidoctorInstance(Collections.singletonMap(GEM_PATH, gemPath), new ArrayList<>(), classloader),
+                classloader);
     }
 
     public static JRubyAsciidoctor create(List<String> loadPaths, String gemPath) {
@@ -96,22 +100,49 @@ private static JRubyAsciidoctor processRegistrations(JRubyAsciidoctor asciidocto
         return asciidoctor;
     }
 
+    private static JRubyAsciidoctor processRegistrations(JRubyAsciidoctor asciidoctor, ClassLoader classloader) {
+        registerExtensions(asciidoctor, classloader);
+        registerConverters(asciidoctor, classloader);
+        registerSyntaxHighlighters(asciidoctor, classloader);
+        registerLogHandlers(asciidoctor, classloader);
+
+        JavaLogger.install(asciidoctor.getRubyRuntime(), asciidoctor);
+
+        return asciidoctor;
+    }
+
     private static void registerConverters(AsciidoctorJRuby asciidoctor) {
         new ConverterRegistryExecutor(asciidoctor).registerAllConverters();
     }
 
+    private static void registerConverters(AsciidoctorJRuby asciidoctor, ClassLoader classloader) {
+        new ConverterRegistryExecutor(asciidoctor).registerAllConverters(classloader);
+    }
+
     private static void registerExtensions(AsciidoctorJRuby asciidoctor) {
         new ExtensionRegistryExecutor(asciidoctor).registerAllExtensions();
     }
 
+    private static void registerExtensions(AsciidoctorJRuby asciidoctor, ClassLoader classloader) {
+        new ExtensionRegistryExecutor(asciidoctor).registerAllExtensions(classloader);
+    }
+
     private static void registerSyntaxHighlighters(AsciidoctorJRuby asciidoctor) {
         new SyntaxHighlighterRegistryExecutor(asciidoctor).registerAllSyntaxHighlighter();
     }
 
+    private static void registerSyntaxHighlighters(AsciidoctorJRuby asciidoctor, ClassLoader classloader) {
+        new SyntaxHighlighterRegistryExecutor(asciidoctor).registerAllSyntaxHighlighter(classloader);
+    }
+
     private static void registerLogHandlers(AsciidoctorJRuby asciidoctor) {
         new LogHandlerRegistryExecutor(asciidoctor).registerAllLogHandlers();
     }
 
+    private static void registerLogHandlers(AsciidoctorJRuby asciidoctor, ClassLoader classloader) {
+        new LogHandlerRegistryExecutor(asciidoctor).registerAllLogHandlers(classloader);
+    }
+
     private static JRubyAsciidoctor createJRubyAsciidoctorInstance(Map<String, String> environmentVars, List<String> loadPaths, ClassLoader classloader) {
         Ruby rubyRuntime = createRubyRuntime(environmentVars, loadPaths, classloader);
         return new JRubyAsciidoctor(rubyRuntime);
diff --git a/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/log/internal/LogHandlerRegistryExecutor.java b/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/log/internal/LogHandlerRegistryExecutor.java
index 74613c9a..947ffba7 100644
--- a/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/log/internal/LogHandlerRegistryExecutor.java
+++ b/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/log/internal/LogHandlerRegistryExecutor.java
@@ -6,8 +6,6 @@
 import java.util.ServiceLoader;
 
 public class LogHandlerRegistryExecutor {
-    private static ServiceLoader<LogHandler> logHandlerServiceLoader = ServiceLoader
-        .load(LogHandler.class);
 
     private AsciidoctorJRuby asciidoctor;
 
@@ -16,6 +14,13 @@ public LogHandlerRegistryExecutor(AsciidoctorJRuby asciidoctor) {
     }
 
     public void registerAllLogHandlers() {
+        registerAllLogHandlers(Thread.currentThread().getContextClassLoader());
+    }
+
+    public void registerAllLogHandlers(ClassLoader classloader) {
+        ServiceLoader<LogHandler> logHandlerServiceLoader = ServiceLoader
+                .load(LogHandler.class, classloader);
+
         for (LogHandler logHandler: logHandlerServiceLoader) {
             asciidoctor.registerLogHandler(logHandler);
         }
diff --git a/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/syntaxhighlighter/internal/SyntaxHighlighterRegistryExecutor.java b/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/syntaxhighlighter/internal/SyntaxHighlighterRegistryExecutor.java
index 5923935c..590d83f7 100644
--- a/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/syntaxhighlighter/internal/SyntaxHighlighterRegistryExecutor.java
+++ b/asciidoctorj-core/src/main/java/org/asciidoctor/jruby/syntaxhighlighter/internal/SyntaxHighlighterRegistryExecutor.java
@@ -15,9 +15,13 @@ public SyntaxHighlighterRegistryExecutor(AsciidoctorJRuby asciidoctor) {
     }
 
     public void registerAllSyntaxHighlighter() {
+        registerAllSyntaxHighlighter(Thread.currentThread().getContextClassLoader());
+    }
+
+    public void registerAllSyntaxHighlighter(ClassLoader classLoader) {
         ServiceLoader<SyntaxHighlighterRegistry> serviceLoader = ServiceLoader
-                .load(SyntaxHighlighterRegistry.class);
-        
+                .load(SyntaxHighlighterRegistry.class, classLoader);
+
         for (SyntaxHighlighterRegistry extensionRegistry : serviceLoader) {
             extensionRegistry.register(asciidoctor);
         }