title: In CustomAbstracthandler, Modify Httpfield is not working in jetty server 11 version
body: <p>Getting header <code>Connection: close, upgrade</code> from Client, so I am trying to change connection header from <code>connection: close, upgrade</code> to <code>connection: Upgrade</code>.</p>
  <p>I modified  httpfield in CustomAbstractHandler, but not working in Jetty 11 version.</p>
  <p>CustomAbstractHandler.Java :</p>
  <pre class="lang-java prettyprint-override"><code>import java.io.IOException;
  import org.eclipse.jetty.http.HttpFields;
  import org.eclipse.jetty.server.Request;
  import org.eclipse.jetty.server.handler.AbstractHandler;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import jakarta.servlet.ServletException;
  import jakarta.servlet.http.HttpServletRequest;
  import jakarta.servlet.http.HttpServletResponse;
  
  public class CustomAbstractHandler extends AbstractHandler {
      private static final Logger LOG = LoggerFactory.getLogger(CustomAbstractHandler.class);
      @Override
      public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response)
              throws IOException, ServletException {
          HttpFields.Mutable replacement = HttpFields.build(baseRequest.getHttpFields()).put(&quot;Connection&quot;, &quot;Upgrade&quot;);
          baseRequest.setHttpFields(replacement);
          LOG.info(&quot;&quot; + baseRequest.getHttpFields());
          baseRequest.setHandled(true);
      }
  }
         
  </code></pre>
  <p>In Main Class configure Handler in <code>server.setHandler()</code></p>
  <pre class="lang-java prettyprint-override"><code>import java.util.EnumSet;
  import org.eclipse.jetty.server.Server;
  import org.eclipse.jetty.server.ServerConnector;
  import org.eclipse.jetty.servlet.FilterHolder;
  import org.eclipse.jetty.servlet.ServletContextHandler;
  import org.eclipse.jetty.websocket.server.config.JettyWebSocketServletContainerInitializer;
  import jakarta.servlet.DispatcherType;
  
  public class WebSocketServer {
      private static Server server;
  
      public static void main(String args[]) throws Exception {
          server = new Server();
          server.setStopTimeout(100);
          ServerConnector connector = new ServerConnector(server);
          connector.setIdleTimeout(1000 * 60 * 60);
          connector.setPort(56667);
          connector.setAcceptedTcpNoDelay(true);
          connector.setAccepting(true);
          connector.join(100);
          connector.setAcceptedReceiveBufferSize(1234567889);
          connector.getConnectedEndPoints();
          server.addConnector(connector);
          ServletContextHandler contextHandler = new ServletContextHandler(ServletContextHandler.SESSIONS);
          contextHandler.setContextPath(&quot;/shop&quot;);
          FilterHolder filterHolder = contextHandler.addFilter(websocketcreator.class, &quot;/*&quot;,
                  EnumSet.of(DispatcherType.REQUEST));
          filterHolder.setAsyncSupported(true);
          contextHandler.getSessionHandler().setMaxInactiveInterval(5);
          server.setHandler(new CustomAbstractHandler());
          contextHandler.addServlet(WebSocketServerServlet.class, &quot;/web-socket/&quot;);
          JettyWebSocketServletContainerInitializer.configure(contextHandler, null);
          server.setHandler(contextHandler);
          server.start();
          server.dump(System.err);
          server.join();
      }
  
  </code></pre>
  <p>Anything wrong from the code?</p>