--- a/src/jdk.incubator.httpclient/share/classes/jdk/incubator/http/internal/websocket/Receiver.java	Wed Nov 29 16:59:38 2017 +0000
+++ b/src/jdk.incubator.httpclient/share/classes/jdk/incubator/http/internal/websocket/Receiver.java	Thu Nov 30 13:35:26 2017 +0300
@@ -25,13 +25,13 @@
 
 package jdk.incubator.http.internal.websocket;
 
+import jdk.incubator.http.internal.common.Demand;
+import jdk.incubator.http.internal.common.SequentialScheduler;
+
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.channels.SelectionKey;
 
-import jdk.incubator.http.internal.common.Demand;
-import jdk.incubator.http.internal.common.SequentialScheduler;
-
 /*
  * Receives incoming data from the channel on demand and converts it into a
  * stream of WebSocket messages which are then delivered to the supplied message
@@ -101,11 +101,9 @@
     }
 
     public void request(long n) {
-        if (n <= 0L) {
-            throw new IllegalArgumentException("Non-positive request: " + n);
+        if (demand.increase(n)) {
+            pushScheduler.runOrSchedule();
         }
-        demand.increase(n);
-        pushScheduler.runOrSchedule();
     }
 
     /*