src/jdk.incubator.httpclient/share/classes/jdk/incubator/http/PlainHttpConnection.java

*** 141,159 ****
          super(addr, client);
          try {
              this.chan = SocketChannel.open();
              chan.configureBlocking(false);
              int bufsize = client.getReceiveBufferSize();
!             chan.setOption(StandardSocketOptions.SO_RCVBUF, bufsize);
              chan.setOption(StandardSocketOptions.TCP_NODELAY, true);
              // wrap the connected channel in a Tube for async reading and writing
              tube = new SocketTube(client(), chan, Utils::getBuffer);
          } catch (IOException e) {
              throw new InternalError(e);
          }
      }
  
      @Override
      HttpPublisher publisher() { return writePublisher; }
  
  
      @Override
--- 141,173 ----
          super(addr, client);
          try {
              this.chan = SocketChannel.open();
              chan.configureBlocking(false);
              int bufsize = client.getReceiveBufferSize();
!             if (!trySetReceiveBufferSize(bufsize)) {
!                 trySetReceiveBufferSize(256*1024);
!             }
              chan.setOption(StandardSocketOptions.TCP_NODELAY, true);
              // wrap the connected channel in a Tube for async reading and writing
              tube = new SocketTube(client(), chan, Utils::getBuffer);
          } catch (IOException e) {
              throw new InternalError(e);
          }
      }
  
+     private boolean trySetReceiveBufferSize(int bufsize) {
+         try {
+             chan.setOption(StandardSocketOptions.SO_RCVBUF, bufsize);
+             return true;
+         } catch(IOException x) {
+             debug.log(Level.DEBUG,
+                     "Failed to set receive buffer size to %d on %s",
+                     bufsize, chan);
+         }
+         return false;
+     }
+ 
      @Override
      HttpPublisher publisher() { return writePublisher; }
  
  
      @Override