Grizzly http server fails some request

Question

Hi, I created a grizzly web server, to run my jersey application out of tomcat, to speed up tests.

I'm a grizzly beginner, but looking through the net I put some code lines together, to make a grizzly web server up and running in less than a working day :)

Unfortunately my class has some troubles on concurrent request, often one or more fails in an inexplicable NullPointerException.

Troubles are typically when I refresh my web page, where grizzly must return about 25 non cached files. This is registered exception:

9-set-2010 10.45.21 com.sun.grizzly.http.servlet.ServletAdapter doService
GRAVE: service exception:
java.lang.NullPointerException
    at com.sun.grizzly.http.servlet.FilterChainImpl.doFilter(FilterChainImpl.java:178)
    at com.sun.grizzly.http.servlet.FilterChainImpl.invokeFilterChain(FilterChainImpl.java:139)
    at com.sun.grizzly.http.servlet.ServletAdapter.doService(ServletAdapter.java:376)
    at com.sun.grizzly.http.servlet.ServletAdapter.service(ServletAdapter.java:324)
.....

Static files are served from a class of mine, but logs tells me everithing is ok and when I use application under tomcat, everything is ok. I really don't know how to solve this problem..

This is the code I created/copied from internet, to startup project:

public class LaunchApp {

/** Find in internet, used to use argument port as default, only if there is no JERSEY_HTTP_PORT env port enabled*/
private static int getPort(int defaultPort) {
    String port = System.getenv("JERSEY_HTTP_PORT");
    if (null != port) {
        try {
            return Integer.parseInt(port);
        } catch (NumberFormatException e) {
        }
    }
    return defaultPort;
}

private static URI getBaseURI() {
    return UriBuilder.fromUri("http://localhost/").port(getPort(8080)).build();
}

public static final URI BASE_URI = getBaseURI();

protected static GrizzlyWebServer startServer() throws IOException {
    final String rootFolder = "/Users/davide/dev/my-project/src/main/webapp";
    GrizzlyWebServer ws = new GrizzlyWebServer("/Users/davide/dev/my-project/src/main/webapp");
    try{
        ServletAdapter adapter = new ServletAdapter();
        adapter.addContextParameter( "contextConfigLocation","classpath:applicationContext.xml" );
        adapter.addServletListener("org.springframework.web.context.ContextLoaderListener");
        adapter.addServletListener("org.springframework.web.context.request.RequestContextListener");
        adapter.addInitParameter( "com.sun.jersey.config.property.packages", "it.treis.zero.web.rest");
        adapter.addInitParameter( "com.sun.jersey.spi.container.ContainerRequestFilters","com.sun.jersey.api.container.filter.LoggingFilter");
        adapter.addInitParameter( "com.sun.jersey.spi.container.ContainerResponseFilters","com.sun.jersey.api.container.filter.LoggingFilter");
        adapter.setProperty( "load-on-startup", 1 );
        adapter.setServletInstance( new SpringServlet() );
        adapter.setRootFolder(rootFolder);

        // Add Open Session In View Hibernate Filter.
        adapter.addFilter(new org.springframework.orm.hibernate3.support.OpenSessionInViewFilter(), "openSessionInViewFilter", null);

        ws.addGrizzlyAdapter(adapter);

        ws.start();
    } catch(IOException ex){
        ex.printStackTrace();
    }
    return ws;
}

public static void main(String[] args) throws IOException {
    System.out.println("Starting Jersey");
    GrizzlyWebServer ws = startServer();
    System.out.println("Jersey rightly started, press any key to shutdown");
    System.in.read();
    ws.stop();
    System.exit(0);
}
}

Any suggestions are appreciated.

Ciao, Davide.