src/jdk.net/share/classes/jdk/net/Sockets.java

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2017, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this

@@ -257,10 +257,25 @@
             checkedReusePort = true;
         }
         return isReusePortAvailable;
     }
 
+    private static volatile boolean isQuickAckAvailable;
+    private static volatile boolean checkedQuickAck;
+
+    /**
+     * Tells whether SO_QUICKACK is supported.
+     */
+    static boolean isQuickAckAvailable() {
+        if (!checkedQuickAck) {
+            Set<SocketOption<?>> s = new Socket().supportedOptions();
+            isQuickAckAvailable = s.contains(ExtendedSocketOptions.SO_QUICKACK);
+            checkedQuickAck = true;
+        }
+        return isQuickAckAvailable;
+    }
+    
     private static Map<Class<?>,Set<SocketOption<?>>> optionSets() {
         Map<Class<?>,Set<SocketOption<?>>> options = new HashMap<>();
         boolean flowsupported = PlatformSocketOptions.get().flowSupported();
         boolean reuseportsupported = isReusePortAvailable();
         // Socket

@@ -277,10 +292,13 @@
         set.add(StandardSocketOptions.IP_TOS);
         set.add(StandardSocketOptions.TCP_NODELAY);
         if (flowsupported) {
             set.add(ExtendedSocketOptions.SO_FLOW_SLA);
         }
+        if (isQuickAckAvailable()) {
+            set.add(ExtendedSocketOptions.SO_QUICKACK);
+        }
         set = Collections.unmodifiableSet(set);
         options.put(Socket.class, set);
 
         // ServerSocket
 

@@ -288,10 +306,13 @@
         set.add(StandardSocketOptions.SO_RCVBUF);
         set.add(StandardSocketOptions.SO_REUSEADDR);
         if (reuseportsupported) {
             set.add(StandardSocketOptions.SO_REUSEPORT);
         }
+        if (isQuickAckAvailable()) {
+            set.add(ExtendedSocketOptions.SO_QUICKACK);
+        }
         set.add(StandardSocketOptions.IP_TOS);
         set = Collections.unmodifiableSet(set);
         options.put(ServerSocket.class, set);
 
         // DatagramSocket