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

*** 1,7 ****
  /*
!  * Copyright (c) 2016, 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
--- 1,7 ----
  /*
!  * 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
*** 277,286 ****
--- 277,289 ----
          set.add(StandardSocketOptions.IP_TOS);
          set.add(StandardSocketOptions.TCP_NODELAY);
          if (flowsupported) {
              set.add(ExtendedSocketOptions.SO_FLOW_SLA);
          }
+         if (QuickAck.available) {
+             set.add(ExtendedSocketOptions.TCP_QUICKACK);
+         }
          set = Collections.unmodifiableSet(set);
          options.put(Socket.class, set);
  
          // ServerSocket
  
*** 288,297 ****
--- 291,303 ----
          set.add(StandardSocketOptions.SO_RCVBUF);
          set.add(StandardSocketOptions.SO_REUSEADDR);
          if (reuseportsupported) {
              set.add(StandardSocketOptions.SO_REUSEPORT);
          }
+         if (QuickAck.available) {
+             set.add(ExtendedSocketOptions.TCP_QUICKACK);
+         }
          set.add(StandardSocketOptions.IP_TOS);
          set = Collections.unmodifiableSet(set);
          options.put(ServerSocket.class, set);
  
          // DatagramSocket
*** 329,334 ****
--- 335,353 ----
          set = Collections.unmodifiableSet(set);
          options.put(MulticastSocket.class, set);
  
          return Collections.unmodifiableMap(options);
      }
+     
+     /**
+      * Tells whether TCP_QUICKACK is supported.
+      */
+     static class QuickAck {
+ 
+         static final boolean available;
+ 
+         static {
+             Set<SocketOption<?>> s = new Socket().supportedOptions();
+             available = s.contains(ExtendedSocketOptions.TCP_QUICKACK);
+         }
+     }
  }