diff --git a/scm-core/src/main/java/sonia/scm/event/EventBusException.java b/scm-core/src/main/java/sonia/scm/event/EventBusException.java
index bc93211b9d..cf193cbdb9 100644
--- a/scm-core/src/main/java/sonia/scm/event/EventBusException.java
+++ b/scm-core/src/main/java/sonia/scm/event/EventBusException.java
@@ -32,10 +32,9 @@
 
 package sonia.scm.event;
 
-import com.google.common.eventbus.ThrowingEventBus;
 
 /**
- * Exception is thrown if from the {@link ThrowingEventBus} an error occurs 
+ * Exception is thrown from the {@link ScmEventBus} if an error occurs 
  * during a synchronous event post operation.
  *
  * @author Sebastian Sdorra
diff --git a/scm-core/src/main/java/sonia/scm/event/ScmEventBus.java b/scm-core/src/main/java/sonia/scm/event/ScmEventBus.java
index b957e7a6b9..4d884185eb 100644
--- a/scm-core/src/main/java/sonia/scm/event/ScmEventBus.java
+++ b/scm-core/src/main/java/sonia/scm/event/ScmEventBus.java
@@ -30,58 +30,45 @@
  */
 
 
+
 package sonia.scm.event;
 
 //~--- non-JDK imports --------------------------------------------------------
 
-import com.google.common.eventbus.AsyncEventBus;
 import com.google.common.eventbus.EventBus;
-import com.google.common.eventbus.ThrowingEventBus;
-
-import org.apache.shiro.concurrent.SubjectAwareExecutorService;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import sonia.scm.util.ServiceUtil;
+
 //~--- JDK imports ------------------------------------------------------------
 
-import java.util.concurrent.Executors;
+import java.util.ServiceLoader;
 
 /**
  * Dispatches events to listeners, and provides ways for listeners to register
- * themselves.
+ * themselves. The ScmEventBus searches its implementation with the
+ * {@link ServiceLoader}.
  *
  * @see {@link EventBus}
  * @author Sebastian Sdorra
  * @since 1.23
- * 
+ *
  * @apiviz.landmark
  */
-public class ScmEventBus extends EventBus
+public abstract class ScmEventBus
 {
 
+  /** Field description */
+  private volatile static ScmEventBus instance;
+
   /**
    * the logger for ScmEventBus
    */
   private static final Logger logger =
     LoggerFactory.getLogger(ScmEventBus.class);
 
-  /** Field description */
-  private static ScmEventBus instance = new ScmEventBus();
-
-  //~--- constructors ---------------------------------------------------------
-
-  /**
-   *  Constructs a new ScmEventBus
-   *
-   */
-  private ScmEventBus()
-  {
-    eventBus = new ThrowingEventBus();
-    asyncEventBus = new AsyncEventBus(
-      new SubjectAwareExecutorService(Executors.newCachedThreadPool()));
-  }
-
   //~--- get methods ----------------------------------------------------------
 
   /**
@@ -92,97 +79,65 @@ public class ScmEventBus extends EventBus
    */
   public static ScmEventBus getInstance()
   {
+    if (instance == null)
+    {
+      synchronized (ScmEventBus.class)
+      {
+        if (instance == null)
+        {
+          instance = ServiceUtil.getService(ScmEventBus.class);
+
+          if (instance == null)
+          {
+            throw new IllegalStateException(
+              "could not find a event bus implementation");
+          }
+          else
+          {
+            logger.info("use {} as event bus implementation",
+              instance.getClass().getName());
+          }
+        }
+      }
+    }
+
     return instance;
   }
 
   //~--- methods --------------------------------------------------------------
 
   /**
-   * {@inheritDoc}
+   * Post a event through the event bus. All registered subscribers will be
+   * notified by the event bus.
    *
-   *
-   * @param event
+   * @param event event to send through the event bus
    */
-  @Override
-  public void post(Object event)
-  {
-    logger.debug("post {} to event bus", event);
-    asyncEventBus.post(event);
-    eventBus.post(event);
-  }
+  public abstract void post(Object event);
 
   /**
-   * {@inheritDoc}
+   * Register all handler methods with the {@link Subscribe} annotation as
+   * subscriber for the event bus.
    *
-   *
-   * @param object
+   * @param subscriber subscriber object
+   * @param async should the subscriber receive the event in async manner
    */
-  @Override
-  public void register(Object object)
-  {
-    register(object, true);
-  }
+  public abstract void register(Object subscriber, boolean async);
 
   /**
-   * Registers a object to the eventbus.
+   * Unregister the given subscriber object from the event bus.
    *
-   * @param object object to register
-   * @param async handle event asynchronously
-   *
-   * @see {@link #register(java.lang.Object)}
+   * @param subscriber subscriber object to unregister
    */
-  public void register(Object object, boolean async)
-  {
-    logger.debug("register {} to event bus, async = {}", object, async);
-
-    if (async)
-    {
-      asyncEventBus.register(object);
-    }
-    else
-    {
-      eventBus.register(object);
-    }
-  }
+  public abstract void unregister(Object subscriber);
 
   /**
-   * {@inheritDoc}
+   * This method is the same as {@code register(subscriber, true)}.
    *
    *
-   * @param object
+   * @param subscriber subscriber object
    */
-  @Override
-  public void unregister(Object object)
+  public void register(Object subscriber)
   {
-    logger.debug("unregister {} from event bus", object);
-    unregister(asyncEventBus, object);
-    unregister(eventBus, object);
+    register(subscriber, true);
   }
-
-  /**
-   * Unregisters the object from eventbus.
-   *
-   *
-   * @param bus event bus
-   * @param object object to unregister
-   */
-  private void unregister(EventBus bus, Object object)
-  {
-    try
-    {
-      bus.unregister(object);
-    }
-    catch (IllegalArgumentException ex)
-    {
-      logger.trace("object {} was not registered at {}", object, bus);
-    }
-  }
-
-  //~--- fields ---------------------------------------------------------------
-
-  /** asynchronous event bus */
-  private AsyncEventBus asyncEventBus;
-
-  /** synchronous event bus */
-  private EventBus eventBus;
 }
diff --git a/scm-core/src/main/java/sonia/scm/event/Subscriber.java b/scm-core/src/main/java/sonia/scm/event/Subscriber.java
index f7397171ff..629ea8e7ed 100644
--- a/scm-core/src/main/java/sonia/scm/event/Subscriber.java
+++ b/scm-core/src/main/java/sonia/scm/event/Subscriber.java
@@ -34,7 +34,6 @@ package sonia.scm.event;
 
 //~--- JDK imports ------------------------------------------------------------
 
-import com.google.common.eventbus.EventBus;
 import com.google.common.eventbus.Subscribe;
 import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;
@@ -47,7 +46,7 @@ import sonia.scm.EagerSingleton;
  * The subscriber annotation could be use to register listener classes to the 
  * {@link ScmEventBus}. A registered listener object can use the 
  * {@link Subscribe} annotation for methods to receive events, 
- * for more informations have a look at {@link EventBus}. The annotated object 
+ * for more informations have a look at {@link ScmEventBus}. The annotated object 
  * is only bind to the {@link ScmEventBus}, if the the object is loaded from the
  * injection system of SCM-Manager. If your object is not loaded by the 
  * injection system you have to register your object by yourself with the 
diff --git a/scm-core/src/main/java/com/google/common/eventbus/ThrowingEventBus.java b/scm-webapp/src/main/java/com/google/common/eventbus/ThrowingEventBus.java
similarity index 99%
rename from scm-core/src/main/java/com/google/common/eventbus/ThrowingEventBus.java
rename to scm-webapp/src/main/java/com/google/common/eventbus/ThrowingEventBus.java
index 4af2af17d0..ae9a0a9112 100644
--- a/scm-core/src/main/java/com/google/common/eventbus/ThrowingEventBus.java
+++ b/scm-webapp/src/main/java/com/google/common/eventbus/ThrowingEventBus.java
@@ -44,7 +44,6 @@ import java.lang.reflect.InvocationTargetException;
  * {@link EventBus} which is able to throw {@link EventBusException}.
  *
  * @author Sebastian Sdorra
- * @since 1.23
  */
 public class ThrowingEventBus extends EventBus
 {
diff --git a/scm-webapp/src/main/java/sonia/scm/ScmServletModule.java b/scm-webapp/src/main/java/sonia/scm/ScmServletModule.java
index 3878466199..424315e8c4 100644
--- a/scm-webapp/src/main/java/sonia/scm/ScmServletModule.java
+++ b/scm-webapp/src/main/java/sonia/scm/ScmServletModule.java
@@ -252,7 +252,6 @@ public class ScmServletModule extends ServletModule
 
     // bind event api
     bind(ScmEventBus.class).toInstance(ScmEventBus.getInstance());
-    bind(EventBus.class).toInstance(ScmEventBus.getInstance());
 
     // bind core
     bind(StoreFactory.class, JAXBStoreFactory.class);
diff --git a/scm-webapp/src/main/java/sonia/scm/event/GuavaScmEventBus.java b/scm-webapp/src/main/java/sonia/scm/event/GuavaScmEventBus.java
new file mode 100644
index 0000000000..d54e51d4e7
--- /dev/null
+++ b/scm-webapp/src/main/java/sonia/scm/event/GuavaScmEventBus.java
@@ -0,0 +1,154 @@
+/**
+ * Copyright (c) 2010, Sebastian Sdorra All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer. 2. Redistributions in
+ * binary form must reproduce the above copyright notice, this list of
+ * conditions and the following disclaimer in the documentation and/or other
+ * materials provided with the distribution. 3. Neither the name of SCM-Manager;
+ * nor the names of its contributors may be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * http://bitbucket.org/sdorra/scm-manager
+ *
+ */
+package sonia.scm.event;
+
+import com.google.common.eventbus.AsyncEventBus;
+import com.google.common.eventbus.EventBus;
+import com.google.common.eventbus.ThrowingEventBus;
+import java.util.concurrent.Executors;
+import org.apache.shiro.concurrent.SubjectAwareExecutorService;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ *
+ * @author Sebastian Sdorra
+ */
+public class GuavaScmEventBus extends ScmEventBus
+{
+  
+  /**
+   * the logger for GuavaScmEventBus
+   */
+  private static final Logger logger = LoggerFactory.getLogger(
+    GuavaScmEventBus.class);
+  
+  
+  /**
+   *  Constructs a new ScmEventBus
+   *
+   */
+  public GuavaScmEventBus()
+  {
+    eventBus = new ThrowingEventBus();
+    asyncEventBus = new AsyncEventBus(
+      new SubjectAwareExecutorService(Executors.newCachedThreadPool()));
+  }
+
+  
+  /**
+   * {@inheritDoc}
+   *
+   *
+   * @param event
+   */
+  @Override
+  public void post(Object event)
+  {
+    logger.debug("post {} to event bus", event);
+    asyncEventBus.post(event);
+    eventBus.post(event);
+  }
+
+  /**
+   * {@inheritDoc}
+   *
+   *
+   * @param object
+   */
+  @Override
+  public void register(Object object)
+  {
+    register(object, true);
+  }
+
+  /**
+   * Registers a object to the eventbus.
+   *
+   * @param object object to register
+   * @param async handle event asynchronously
+   *
+   * @see {@link #register(java.lang.Object)}
+   */
+  @Override
+  public void register(Object object, boolean async)
+  {
+    logger.debug("register {} to event bus, async = {}", object, async);
+
+    if (async)
+    {
+      asyncEventBus.register(object);
+    }
+    else
+    {
+      eventBus.register(object);
+    }
+  }
+
+  /**
+   * {@inheritDoc}
+   *
+   *
+   * @param object
+   */
+  @Override
+  public void unregister(Object object)
+  {
+    logger.debug("unregister {} from event bus", object);
+    unregister(asyncEventBus, object);
+    unregister(eventBus, object);
+  }
+
+  /**
+   * Unregisters the object from eventbus.
+   *
+   *
+   * @param bus event bus
+   * @param object object to unregister
+   */
+  private void unregister(EventBus bus, Object object)
+  {
+    try
+    {
+      bus.unregister(object);
+    }
+    catch (IllegalArgumentException ex)
+    {
+      logger.trace("object {} was not registered at {}", object, bus);
+    }
+  }
+
+  //~--- fields ---------------------------------------------------------------
+
+  /** asynchronous event bus */
+  private AsyncEventBus asyncEventBus;
+
+  /** synchronous event bus */
+  private EventBus eventBus;
+}
diff --git a/scm-webapp/src/main/resources/META-INF/services/sonia.scm.event.ScmEventBus b/scm-webapp/src/main/resources/META-INF/services/sonia.scm.event.ScmEventBus
new file mode 100644
index 0000000000..956fa094d0
--- /dev/null
+++ b/scm-webapp/src/main/resources/META-INF/services/sonia.scm.event.ScmEventBus
@@ -0,0 +1 @@
+sonia.scm.event.GuavaScmEventBus
\ No newline at end of file