diff --git a/src/main/java/com/corundumstudio/socketio/AckManager.java b/src/main/java/com/corundumstudio/socketio/AckManager.java
index 1693f55..cd49f12 100644
--- a/src/main/java/com/corundumstudio/socketio/AckManager.java
+++ b/src/main/java/com/corundumstudio/socketio/AckManager.java
@@ -15,7 +15,6 @@
  */
 package com.corundumstudio.socketio;
 
-import java.util.Collections;
 import java.util.Map;
 import java.util.Set;
 import java.util.UUID;
@@ -29,6 +28,7 @@ import com.corundumstudio.socketio.scheduler.CancelableScheduler;
 import com.corundumstudio.socketio.scheduler.SchedulerKey;
 import com.corundumstudio.socketio.scheduler.SchedulerKey.Type;
 import com.corundumstudio.socketio.transport.BaseClient;
+import com.corundumstudio.socketio.utils.ConcurrentHashSet;
 
 public class AckManager implements Disconnectable {
 
@@ -66,7 +66,7 @@ public class AckManager implements Disconnectable {
     public long registerAck(UUID sessionId, final AckCallback callback) {
         Set<Long> callbackIds = clientCallbackIds.get(sessionId);
         if (callbackIds == null) {
-            callbackIds = Collections.newSetFromMap(new ConcurrentHashMap<Long, Boolean>());
+            callbackIds = new ConcurrentHashSet<Long>();
             Set<Long> oldCallbackIds = clientCallbackIds.putIfAbsent(sessionId, callbackIds);
             if (oldCallbackIds != null) {
                 callbackIds = oldCallbackIds;
diff --git a/src/main/java/com/corundumstudio/socketio/AuthorizeHandler.java b/src/main/java/com/corundumstudio/socketio/AuthorizeHandler.java
index 6ac0503..3762724 100644
--- a/src/main/java/com/corundumstudio/socketio/AuthorizeHandler.java
+++ b/src/main/java/com/corundumstudio/socketio/AuthorizeHandler.java
@@ -51,6 +51,7 @@ import com.corundumstudio.socketio.scheduler.CancelableScheduler;
 import com.corundumstudio.socketio.scheduler.SchedulerKey;
 import com.corundumstudio.socketio.scheduler.SchedulerKey.Type;
 import com.corundumstudio.socketio.transport.BaseClient;
+import com.corundumstudio.socketio.utils.ConcurrentHashSet;
 
 @Sharable
 public class AuthorizeHandler extends SimpleChannelUpstreamHandler implements Disconnectable {
@@ -58,8 +59,7 @@ public class AuthorizeHandler extends SimpleChannelUpstreamHandler implements Di
     private final Logger log = LoggerFactory.getLogger(getClass());
 
     private final CancelableScheduler disconnectScheduler;
-    private final Set<UUID> authorizedSessionIds =
-                                Collections.newSetFromMap(new ConcurrentHashMap<UUID, Boolean>());
+    private final Set<UUID> authorizedSessionIds = new ConcurrentHashSet<UUID>();
 
     private final String connectPath;
     private final Configuration configuration;
diff --git a/src/main/java/com/corundumstudio/socketio/namespace/Namespace.java b/src/main/java/com/corundumstudio/socketio/namespace/Namespace.java
index 44c4512..ea8e438 100644
--- a/src/main/java/com/corundumstudio/socketio/namespace/Namespace.java
+++ b/src/main/java/com/corundumstudio/socketio/namespace/Namespace.java
@@ -15,7 +15,6 @@
  */
 package com.corundumstudio.socketio.namespace;
 
-import java.util.Collections;
 import java.util.Queue;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
@@ -31,12 +30,13 @@ import com.corundumstudio.socketio.listener.DataListener;
 import com.corundumstudio.socketio.listener.DisconnectListener;
 import com.corundumstudio.socketio.parser.JsonSupport;
 import com.corundumstudio.socketio.transport.NamespaceClient;
+import com.corundumstudio.socketio.utils.ConcurrentHashSet;
 
 public class Namespace implements SocketIONamespace {
 
     public static final String DEFAULT_NAME = "";
 
-    private final Set<SocketIOClient> clients = Collections.newSetFromMap(new ConcurrentHashMap<SocketIOClient, Boolean>());
+    private final Set<SocketIOClient> clients = new ConcurrentHashSet<SocketIOClient>();
     private final ConcurrentMap<String, EventEntry<?>> eventListeners =
                                                             new ConcurrentHashMap<String, EventEntry<?>>();
     private final ConcurrentMap<Class<?>, Queue<DataListener<?>>> jsonObjectListeners =
diff --git a/src/main/java/com/corundumstudio/socketio/parser/JacksonJsonSupport.java b/src/main/java/com/corundumstudio/socketio/parser/JacksonJsonSupport.java
index 8651cbc..afa4a00 100644
--- a/src/main/java/com/corundumstudio/socketio/parser/JacksonJsonSupport.java
+++ b/src/main/java/com/corundumstudio/socketio/parser/JacksonJsonSupport.java
@@ -19,7 +19,6 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
@@ -43,12 +42,13 @@ import org.codehaus.jackson.map.module.SimpleModule;
 import org.codehaus.jackson.node.ObjectNode;
 
 import com.corundumstudio.socketio.Configuration;
+import com.corundumstudio.socketio.utils.ConcurrentHashSet;
 
 public class JacksonJsonSupport implements JsonSupport {
 
     private class JsonObjectDeserializer extends StdDeserializer<JsonObject> {
 
-        final Set<Class<?>> classes = Collections.newSetFromMap(new ConcurrentHashMap<Class<?>, Boolean>());
+        final Set<Class<?>> classes = new ConcurrentHashSet<Class<?>>();
 
         protected JsonObjectDeserializer() {
             super(JsonObject.class);