Getting null value while retrieving firewall rules using vCD 5.1 SDK

I am trying to retrieve firewall rules using vCD 5.1 SDK. Please refer to the below code snippet for more details:

vcloudClient.login(userName, password);

ReferenceType adminOrgRef = vcloudClient.getVcloudAdmin().getAdminOrgRefByName(orgName);

AdminOrganization adminOrg = AdminOrganization.getAdminOrgByReference(vcloudClient, adminOrgRef);

ReferenceType adminVdcRef = adminOrg.getAdminVdcRefByName(orgVdcName);

AdminVdc adminVdc = AdminVdc.getAdminVdcByReference(vcloudClient, adminVdcRef);

AdminOrgVdcNetwork admOrgVdcNw = null;
            for(ReferenceType admOrgVdcNwRef : adminVdc.getOrgVdcNetworkRefs().getReferences()){
                if(admOrgVdcNwRef.getName().equalsIgnoreCase(orgNetworkName)){
                    admOrgVdcNw = AdminOrgVdcNetwork.getOrgVdcNetworkByReference(vcloudClient, admOrgVdcNwRef);
                }
            }

if ((admOrgVdcNw.getResource().getConfiguration() != null)&& (admOrgVdcNw.getResource().getConfiguration().getFeatures() != null)) {
                for (JAXBElement<? extends NetworkServiceType> jaxbElement : admOrgVdcNw
                        .getResource().getConfiguration().getFeatures().getNetworkService()) {
                    if (jaxbElement.getValue() instanceof FirewallServiceType) {
                        final FirewallServiceType firewallService = (FirewallServiceType) jaxbElement.getValue();

                                                              
                        for (FirewallRuleType firewallRule : firewallService.getFirewallRule()) {
                            System.out.println("Firewall Desc: " + firewallRule.getDescription());
                        }

                    }
            }
        }

Problem:admOrgVdcNw.getResource().getConfiguration().getFeatures() is returning null. Please tell me where am I going wrong with this.

Is there any other way to get the firewall rules?