Peng.java

import org.eclipse.jetty.http.HttpHeader;
import org.eclipse.jetty.http.HttpParser;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.servlet.ServletContextHandler;

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

public class Peng
{
    public static void main( String... a ) throws Exception
    {

        var context = new ServletContextHandler( ServletContextHandler.SESSIONS );
        context.setContextPath( "/" );

        var jettyServer = new Server( 7921 );

        jettyServer.setHandler( context );
        jettyServer.setRequestLog(
                ( request, response ) -> System.out.println( "Accept reaching server " + request.getHeader( "ACCEPT" ) ) );

        try
        {
            jettyServer.start();
            var client = HttpClient.newHttpClient();
            for ( String s : new String[]{"a", "true", "A", "TRUE"} )
            {
                var accept = "application/json;foo=" + s;
                System.out.println( "With accept " + accept );
                var builder1 = HttpRequest
                        .newBuilder( URI.create( "http://localhost:7921" ) )
                        .header( "ACCEPT", accept )
                        .GET()
                        .build();
                client.send( builder1, HttpResponse.BodyHandlers.discarding() )
                      .statusCode();
             /*
                HttpHeader.CACHE.clear();
                HttpParser.CACHE.clear();
                
              */
            }
        }
        finally
        {
            jettyServer.stop();
        }
    }
}