#vulnerable code 
                                private void updatePresenceStatusForXmppProviders()
    {
        SipGateway gateway = ServiceUtils.getService(
            osgiContext, SipGateway.class);

        int participants = 0;
        for(SipGatewaySession ses : gateway.getActiveSessions())
        {
            participants += ses.getJvbChatRoom().getMembersCount();
        }

        Collection<ServiceReference<ProtocolProviderService>> refs
            = ServiceUtils.getServiceReferences(
                osgiContext,
                ProtocolProviderService.class);

        for (ServiceReference<ProtocolProviderService> ref : refs)
        {
            updatePresenceStatusForXmppProvider(
                gateway, osgiContext.getService(ref), participants);
        }
    } 
                            #location 9 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                private void updatePresenceStatusForXmppProviders()
    {
        Collection<ServiceReference<ProtocolProviderService>> refs
            = ServiceUtils.getServiceReferences(
                osgiContext,
                ProtocolProviderService.class);

        for (ServiceReference<ProtocolProviderService> ref : refs)
        {
            updatePresenceStatusForXmppProvider(osgiContext.getService(ref));
        }
    }