diff --git a/core/src/main/java/org/glassfish/tyrus/core/TyrusSession.java b/core/src/main/java/org/glassfish/tyrus/core/TyrusSession.java
index a7e2df5e..20161f0c 100755
--- a/core/src/main/java/org/glassfish/tyrus/core/TyrusSession.java
+++ b/core/src/main/java/org/glassfish/tyrus/core/TyrusSession.java
@@ -482,9 +482,8 @@ public void setHeartbeatInterval(long heartbeatInterval) {
     }
 
     void restartIdleTimeoutExecutor() {
-        cancelIdleTimeoutExecutor();
-
         synchronized (idleTimeoutLock) {
+            cancelIdleTimeoutExecutor();
             idleTimeoutFuture =
                     service.schedule(new IdleTimeoutCommand(), this.getMaxIdleTimeout(), TimeUnit.MILLISECONDS);
         }