diff --git a/src/main/java/com/corundumstudio/socketio/SocketIOClient.java b/src/main/java/com/corundumstudio/socketio/SocketIOClient.java
index da061f4..88fdd67 100644
--- a/src/main/java/com/corundumstudio/socketio/SocketIOClient.java
+++ b/src/main/java/com/corundumstudio/socketio/SocketIOClient.java
@@ -21,6 +21,11 @@ import java.util.UUID;
 import com.corundumstudio.socketio.parser.Packet;
 
 
+/**
+ * SocketIO client abstraction.
+ * All implementations are thread-safe.
+ *
+ */
 public interface SocketIOClient extends ClientOperations {
 
     /**
diff --git a/src/main/java/com/corundumstudio/socketio/SocketIOServer.java b/src/main/java/com/corundumstudio/socketio/SocketIOServer.java
index ae5c3bf..dfd9a73 100644
--- a/src/main/java/com/corundumstudio/socketio/SocketIOServer.java
+++ b/src/main/java/com/corundumstudio/socketio/SocketIOServer.java
@@ -93,8 +93,7 @@ public class SocketIOServer implements ClientListeners {
      * Start server
      */
     public void start() {
-        EventLoopGroup bossGroup = new NioEventLoopGroup();
-        EventLoopGroup workerGroup = new NioEventLoopGroup();
+        initGroups();
 
         pipelineFactory.start(configCopy, namespacesHub);
         ServerBootstrap b = new ServerBootstrap();
@@ -113,6 +112,11 @@ public class SocketIOServer implements ClientListeners {
         log.info("SocketIO server started at port: {}", configCopy.getPort());
     }
 
+    protected void initGroups() {
+        bossGroup = new NioEventLoopGroup(configCopy.getBossThreads());
+        workerGroup = new NioEventLoopGroup(configCopy.getWorkerThreads());
+    }
+
     /**
      * Stop server
      */