if (System.getProperty("com.sun.enterprise.web.useWebcore") != null){
            useWebcore = Boolean.parseBoolean(
                  System.getProperty("com.sun.enterprise.web.useWebcore"));
        }
            
        VirtualServer vs = null;
        if ( useWebcore ) {    
             /*
             * Ideally, this would be as simple as:
             *
             *     return new com.sun.enterprise.web.HttpServiceVirtualServer();
             * 
             * but importing this class would cause a circular dependency
             * between appserv-core-ee and appserv-pwc-linkage
             */
            try {
                vs = (VirtualServer) Class.forName("com.sun.enterprise.web.HttpServiceVirtualServer").newInstance();
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        } else {
            vs = new VirtualServer();
        }   
        return vs;
    }