#fixed code
                                private String resolveV3(URLResolverParams p) {
        Token token = p.token;

        //in v3 api, if user has no default project, and token is unscoped, no catalog will be returned
        //then if service is Identity service, should directly return the endpoint back
        if (token.getCatalog() == null) {
            if (ServiceType.IDENTITY.equals(p.type)) {
                return token.getEndpoint();
            } else {
                return null;
            }
        }

        for (org.openstack4j.model.identity.v3.Service service : token.getCatalog()) {
            if (p.type == ServiceType.forName(service.getType())) {
                if (p.perspective == null) {
                    p.perspective = Facing.PUBLIC;
                }

                for (org.openstack4j.model.identity.v3.Endpoint ep : service.getEndpoints()) {

                    if (matches(ep, p))
                        return ep.getUrl().toString();
                }
            }
        }


        return null;
    }
#vulnerable code 
                                private String resolveV3(URLResolverParams p) {
        Token token = p.token;

        //in v3 api, if user has no default project, and token is unscoped, no catalog will be returned
        //then if service is Identity service, should directly return the endpoint back
        if (token.getCatalog() == null) {
            if (ServiceType.IDENTITY.equals(p.type)) {
                return token.getEndpoint();
            }
        }

        for (org.openstack4j.model.identity.v3.Service service : token.getCatalog()) {
            if (p.type == ServiceType.forName(service.getType())) {
                if (p.perspective == null) {
                    p.perspective = Facing.PUBLIC;
                }

                for (org.openstack4j.model.identity.v3.Endpoint ep : service.getEndpoints()) {

                    if (matches(ep, p)) {
                        //some installation have v2.0 url in catalog for v3 identity api
                        //some other the url does not have version in it
                        //so we do an additional check here for identity service only
                        if (ServiceType.IDENTITY.equals(ServiceType.forName(service.getType()))) {
                            String v3Url = ep.getUrl().toString();
                            if (v3Url.endsWith("/v3") || v3Url.endsWith("/v3/") ) {
                            } else if (v3Url.endsWith("/v2.0") || v3Url.endsWith("/v2.0/") ) {
                                v3Url =  v3Url.replace("v2.0", "v3");
                            } else {
                                v3Url = v3Url + "/v3";
                            }
                            LOG.trace("resolved v3 endpoint for identity service: {}", v3Url);
                            return v3Url;
                        } else {
                            return ep.getUrl().toString();
                        }
                    }
                }
            }
        }


        return null;
    } 
                            #location 12 
                            #vulnerability type NULL_DEREFERENCE