diff --git a/src/main/java/org/bdware/server/nodecenter/NodeCenterFrameHandler.java b/src/main/java/org/bdware/server/nodecenter/NodeCenterFrameHandler.java
index 4496e87..26ebd63 100644
--- a/src/main/java/org/bdware/server/nodecenter/NodeCenterFrameHandler.java
+++ b/src/main/java/org/bdware/server/nodecenter/NodeCenterFrameHandler.java
@@ -82,7 +82,7 @@ public class NodeCenterFrameHandler extends SimpleChannelInboundHandler<Object>
         try {
             map =
                     JsonParser.parseReader(
-                                    new InputStreamReader(new ByteBufInputStream((ByteBuf) frame)))
+                            new InputStreamReader(new ByteBufInputStream((ByteBuf) frame)))
                             .getAsJsonObject();
 
         } catch (Exception e) {
@@ -136,7 +136,7 @@ public class NodeCenterFrameHandler extends SimpleChannelInboundHandler<Object>
         }
     }
 
-    public void sendMsg(String json) {
+    public synchronized void sendMsg(String json) {
         if (ctx != null) {
             // System.out.println("[NodeCenterFrame send] TID:" + Thread.currentThread().getId() + "
             // isOpen:"