diff --git a/src/main/java/net/engio/mbassy/common/AbstractConcurrentSet.java b/src/main/java/net/engio/mbassy/common/AbstractConcurrentSet.java
index b916a82..003f5da 100644
--- a/src/main/java/net/engio/mbassy/common/AbstractConcurrentSet.java
+++ b/src/main/java/net/engio/mbassy/common/AbstractConcurrentSet.java
@@ -28,18 +28,16 @@ public abstract class AbstractConcurrentSet<T> implements IConcurrentSet<T> {
     protected abstract Entry<T> createEntry(T value, Entry<T> next);
 
     @Override
-    public IConcurrentSet<T> add(T element) {
-        if (element == null) return this;
+    public void add(T element) {
+        if (element == null) return;
         Lock writeLock = lock.writeLock();
         writeLock.lock();
         if (element == null || entries.containsKey(element)) {
             writeLock.unlock();
-            return this;
         } else {
             insert(element);
             writeLock.unlock();
         }
-        return this;
     }
 
     @Override
@@ -69,7 +67,7 @@ public abstract class AbstractConcurrentSet<T> implements IConcurrentSet<T> {
     }
 
     @Override
-    public IConcurrentSet<T> addAll(Iterable<T> elements) {
+    public void addAll(Iterable<T> elements) {
         Lock writeLock = lock.writeLock();
         try {
             writeLock.lock();
@@ -81,7 +79,6 @@ public abstract class AbstractConcurrentSet<T> implements IConcurrentSet<T> {
         } finally {
             writeLock.unlock();
         }
-        return this;
     }
 
     @Override
diff --git a/src/main/java/net/engio/mbassy/common/IConcurrentSet.java b/src/main/java/net/engio/mbassy/common/IConcurrentSet.java
index 432e4ed..8afd72a 100644
--- a/src/main/java/net/engio/mbassy/common/IConcurrentSet.java
+++ b/src/main/java/net/engio/mbassy/common/IConcurrentSet.java
@@ -8,13 +8,13 @@ package net.engio.mbassy.common;
  */
 public interface IConcurrentSet<T> extends Iterable<T> {
 
-    IConcurrentSet<T> add(T element);
+    void add(T element);
 
     boolean contains(T element);
 
     int size();
 
-    IConcurrentSet<T> addAll(Iterable<T> elements);
+    void addAll(Iterable<T> elements);
 
     boolean remove(T element);
 }
diff --git a/src/main/java/net/engio/mbassy/listener/MessageHandler.java b/src/main/java/net/engio/mbassy/listener/MessageHandler.java
index 2549e31..c0a9f7b 100644
--- a/src/main/java/net/engio/mbassy/listener/MessageHandler.java
+++ b/src/main/java/net/engio/mbassy/listener/MessageHandler.java
@@ -56,7 +56,7 @@ public class MessageHandler {
             Map<String, Object> properties = new HashMap<String, Object>();
             properties.put(HandlerMethod, handler);
             // add EL filter if a condition is present
-            if(handlerConfig.condition() != null){
+            if(handlerConfig.condition().length() > 0){
                 if (!ElFilter.isELAvailable()) {
                     throw new IllegalStateException("A handler uses an EL filter but no EL implementation is available.");
                 }
diff --git a/src/test/java/net/engio/mbassy/AllTests.java b/src/test/java/net/engio/mbassy/AllTests.java
index 0ab8b16..9df884a 100644
--- a/src/test/java/net/engio/mbassy/AllTests.java
+++ b/src/test/java/net/engio/mbassy/AllTests.java
@@ -22,7 +22,8 @@ import org.junit.runners.Suite;
         DeadMessageTest.class,
         SynchronizedHandlerTest.class,
         SubscriptionManagerTest.class,
-        AsyncFIFOBusTest.class
+        AsyncFIFOBusTest.class,
+        ConditionalHandlers.class
 })
 public class AllTests {
 }
diff --git a/src/test/java/net/engio/mbassy/ConditionTest.java b/src/test/java/net/engio/mbassy/ConditionalHandlers.java
similarity index 95%
rename from src/test/java/net/engio/mbassy/ConditionTest.java
rename to src/test/java/net/engio/mbassy/ConditionalHandlers.java
index 07993c8..9f32445 100644
--- a/src/test/java/net/engio/mbassy/ConditionTest.java
+++ b/src/test/java/net/engio/mbassy/ConditionalHandlers.java
@@ -1,168 +1,168 @@
-package net.engio.mbassy;
-
-import net.engio.mbassy.bus.MBassador;
-import net.engio.mbassy.bus.config.BusConfiguration;
-import net.engio.mbassy.common.MessageBusTest;
-import net.engio.mbassy.listener.Enveloped;
-import net.engio.mbassy.listener.Handler;
-import net.engio.mbassy.listener.Listener;
-import net.engio.mbassy.listener.References;
-import net.engio.mbassy.subscription.MessageEnvelope;
-import org.junit.Test;
-
-import java.util.HashSet;
-import java.util.Set;
-
-/*****************************************************************************
- * Some unit tests for the "condition" filter.
- ****************************************************************************/
-
-public class ConditionTest extends MessageBusTest {
-
-	public static class TestEvent {
-
-		private Set<String> handledBy = new HashSet<String>();
-		private String type;
-		private int size;
-
-		public TestEvent(String type, int size) {
-			super();
-			this.type = type;
-			this.size = size;
-		}
-		
-		public String getType() {
-			return type;
-		}
-
-		public int getSize() {
-			return size;
-		}
-
-        public boolean wasHandledBy(String ...handlers){
-            for(String handler : handlers){
-                if (!handledBy.contains(handler)) return false;
-            }
-            return true;
-        }
-
-        public void handledBy(String handler){
-            handledBy.add(handler);
-        }
-		
-	}
-
-    @Listener(references = References.Strong)
-	public static class ConditionalMessageListener {
-
-		@Handler(condition = "msg.type == 'TEST'")
-		public void handleTypeMessage(TestEvent message) {
-			message.handledBy("handleTypeMessage");
-		}
-
-		@Handler(condition = "msg.size > 4")
-		public void handleSizeMessage(TestEvent message) {
-			message.handledBy("handleSizeMessage");
-		}
-
-        @Handler(condition = "msg.foo > 4")
-        public void handleInvalidEL(TestEvent message) {
-            message.handledBy("handleInvalidEL");
-        }
-		
-		@Handler(condition = "msg.size > 2 && msg.size < 4")
-		public void handleCombinedEL(TestEvent message) {
-			message.handledBy( "handleCombinedEL");
-		}
-		
-		@Handler(condition = "msg.getType().equals('XYZ') && msg.getSize() == 1")
-		public void handleMethodAccessEL(TestEvent message) {
-			message.handledBy("handleMethodAccessEL");
-		}
-
-        @Handler(condition = "msg.type == 'TEST'")
-        @Enveloped(messages = {TestEvent.class, Object.class})
-        public void handleEnvelopedMessage(MessageEnvelope envelope) {
-            envelope.<TestEvent>getMessage().handledBy("handleEnvelopedMessage");
-        }
-		
-	}
-
-
-	/*************************************************************************
-	 * @throws Exception
-	 ************************************************************************/
-	@Test
-	public void testSimpleStringCondition() throws Exception {
-		MBassador bus = getBus(BusConfiguration.Default());
-		bus.subscribe(new ConditionalMessageListener());
-
-		TestEvent message = new TestEvent("TEST", 0);
-		bus.publish(message);
-
-		assertTrue(message.wasHandledBy("handleTypeMessage", "handleEnvelopedMessage"));
-        assertFalse(message.wasHandledBy("handleInvalidEL"));
-	}
-
-
-	/*************************************************************************
-	 * @throws Exception
-	 ************************************************************************/
-	@Test
-	public void testSimpleNumberCondition() throws Exception {
-		MBassador bus = getBus(BusConfiguration.Default());
-		bus.subscribe(new ConditionalMessageListener());
-
-		TestEvent message = new TestEvent("", 5);
-		bus.publish(message);
-
-		assertTrue(message.wasHandledBy("handleSizeMessage"));
-        assertFalse(message.wasHandledBy("handleInvalidEL"));
-	}
-	
-	/*************************************************************************
-	 * @throws Exception
-	 ************************************************************************/
-	@Test
-	public void testHandleCombinedEL() throws Exception {
-		MBassador bus = getBus(BusConfiguration.Default());
-		bus.subscribe(new ConditionalMessageListener());
-
-		TestEvent message = new TestEvent("", 3);
-		bus.publish(message);
-
-        assertTrue(message.wasHandledBy("handleCombinedEL"));
-        assertFalse(message.wasHandledBy("handleInvalidEL"));
-	}
-	
-	/*************************************************************************
-	 * @throws Exception
-	 ************************************************************************/
-	@Test
-	public void testNotMatchingAnyCondition() throws Exception {
-		MBassador bus = getBus(BusConfiguration.Default());
-		bus.subscribe(new ConditionalMessageListener());
-
-		TestEvent message = new TestEvent("", 0);
-		bus.publish(message);
-
-		assertTrue(message.handledBy.isEmpty());
-	}
-	
-	/*************************************************************************
-	 * @throws Exception
-	 ************************************************************************/
-	@Test
-	public void testHandleMethodAccessEL() throws Exception {
-		MBassador bus = getBus(BusConfiguration.Default());
-		bus.subscribe(new ConditionalMessageListener());
-
-		TestEvent message = new TestEvent("XYZ", 1);
-		bus.publish(message);
-
-        assertTrue(message.wasHandledBy("handleMethodAccessEL"));
-        assertFalse(message.wasHandledBy("handleInvalidEL"));
-
-    }
-
-}
+package net.engio.mbassy;
+
+import net.engio.mbassy.bus.MBassador;
+import net.engio.mbassy.bus.config.BusConfiguration;
+import net.engio.mbassy.common.MessageBusTest;
+import net.engio.mbassy.listener.Enveloped;
+import net.engio.mbassy.listener.Handler;
+import net.engio.mbassy.listener.Listener;
+import net.engio.mbassy.listener.References;
+import net.engio.mbassy.subscription.MessageEnvelope;
+import org.junit.Test;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/*****************************************************************************
+ * Some unit tests for the "condition" filter.
+ ****************************************************************************/
+
+public class ConditionalHandlers extends MessageBusTest {
+
+	public static class TestEvent {
+
+		private Set<String> handledBy = new HashSet<String>();
+		private String type;
+		private int size;
+
+		public TestEvent(String type, int size) {
+			super();
+			this.type = type;
+			this.size = size;
+		}
+		
+		public String getType() {
+			return type;
+		}
+
+		public int getSize() {
+			return size;
+		}
+
+        public boolean wasHandledBy(String ...handlers){
+            for(String handler : handlers){
+                if (!handledBy.contains(handler)) return false;
+            }
+            return true;
+        }
+
+        public void handledBy(String handler){
+            handledBy.add(handler);
+        }
+		
+	}
+
+    @Listener(references = References.Strong)
+	public static class ConditionalMessageListener {
+
+		@Handler(condition = "msg.type == 'TEST'")
+		public void handleTypeMessage(TestEvent message) {
+			message.handledBy("handleTypeMessage");
+		}
+
+		@Handler(condition = "msg.size > 4")
+		public void handleSizeMessage(TestEvent message) {
+			message.handledBy("handleSizeMessage");
+		}
+
+        @Handler(condition = "msg.foo > 4")
+        public void handleInvalidEL(TestEvent message) {
+            message.handledBy("handleInvalidEL");
+        }
+		
+		@Handler(condition = "msg.size > 2 && msg.size < 4")
+		public void handleCombinedEL(TestEvent message) {
+			message.handledBy( "handleCombinedEL");
+		}
+		
+		@Handler(condition = "msg.getType().equals('XYZ') && msg.getSize() == 1")
+		public void handleMethodAccessEL(TestEvent message) {
+			message.handledBy("handleMethodAccessEL");
+		}
+
+        @Handler(condition = "msg.type == 'TEST'")
+        @Enveloped(messages = {TestEvent.class, Object.class})
+        public void handleEnvelopedMessage(MessageEnvelope envelope) {
+            envelope.<TestEvent>getMessage().handledBy("handleEnvelopedMessage");
+        }
+		
+	}
+
+
+	/*************************************************************************
+	 * @throws Exception
+	 ************************************************************************/
+	@Test
+	public void testSimpleStringCondition() throws Exception {
+		MBassador bus = getBus(BusConfiguration.Default());
+		bus.subscribe(new ConditionalMessageListener());
+
+		TestEvent message = new TestEvent("TEST", 0);
+		bus.publish(message);
+
+		assertTrue(message.wasHandledBy("handleTypeMessage", "handleEnvelopedMessage"));
+        assertFalse(message.wasHandledBy("handleInvalidEL"));
+	}
+
+
+	/*************************************************************************
+	 * @throws Exception
+	 ************************************************************************/
+	@Test
+	public void testSimpleNumberCondition() throws Exception {
+		MBassador bus = getBus(BusConfiguration.Default());
+		bus.subscribe(new ConditionalMessageListener());
+
+		TestEvent message = new TestEvent("", 5);
+		bus.publish(message);
+
+		assertTrue(message.wasHandledBy("handleSizeMessage"));
+        assertFalse(message.wasHandledBy("handleInvalidEL"));
+	}
+	
+	/*************************************************************************
+	 * @throws Exception
+	 ************************************************************************/
+	@Test
+	public void testHandleCombinedEL() throws Exception {
+		MBassador bus = getBus(BusConfiguration.Default());
+		bus.subscribe(new ConditionalMessageListener());
+
+		TestEvent message = new TestEvent("", 3);
+		bus.publish(message);
+
+        assertTrue(message.wasHandledBy("handleCombinedEL"));
+        assertFalse(message.wasHandledBy("handleInvalidEL"));
+	}
+	
+	/*************************************************************************
+	 * @throws Exception
+	 ************************************************************************/
+	@Test
+	public void testNotMatchingAnyCondition() throws Exception {
+		MBassador bus = getBus(BusConfiguration.Default());
+		bus.subscribe(new ConditionalMessageListener());
+
+		TestEvent message = new TestEvent("", 0);
+		bus.publish(message);
+
+		assertTrue(message.handledBy.isEmpty());
+	}
+	
+	/*************************************************************************
+	 * @throws Exception
+	 ************************************************************************/
+	@Test
+	public void testHandleMethodAccessEL() throws Exception {
+		MBassador bus = getBus(BusConfiguration.Default());
+		bus.subscribe(new ConditionalMessageListener());
+
+		TestEvent message = new TestEvent("XYZ", 1);
+		bus.publish(message);
+
+        assertTrue(message.wasHandledBy("handleMethodAccessEL"));
+        assertFalse(message.wasHandledBy("handleInvalidEL"));
+
+    }
+
+}
diff --git a/src/test/java/net/engio/mbassy/common/ListenerFactory.java b/src/test/java/net/engio/mbassy/common/ListenerFactory.java
index 7624c7a..d188f6c 100644
--- a/src/test/java/net/engio/mbassy/common/ListenerFactory.java
+++ b/src/test/java/net/engio/mbassy/common/ListenerFactory.java
@@ -30,7 +30,7 @@ public class ListenerFactory {
         return this;
     }
 
-    public ListenerFactory create(int numberOfInstances, Class[] classes){
+    public ListenerFactory create(int numberOfInstances, Class ...classes){
         for(Class clazz : classes)
             create(numberOfInstances,clazz);
         return this;