#vulnerable code 
                                @Override
    public Future<JsonObject> fetchModule(final String appId, final String entry) {
        final JsonObject filters = new JsonObject()
                .put("", Boolean.TRUE)
                .put("entry", entry)
                .put("appId", appId);
        return Ux.Jooq.on(XModuleDao.class)
                .fetchOneAsync(filters)
                .compose(Ux::fnJObject)
                /* Metadata field usage */
                .compose(Ke.mount(KeField.METADATA));
    } 
                            #location 8 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Override
    public Future<JsonObject> fetchModule(final String appId, final String entry) {
        final JsonObject filters = new JsonObject()
                .put("", Boolean.TRUE)
                .put("entry", entry)
                .put("appId", appId);
        /*
         * Cache Module for future usage
         */
        return AcCache.getModule(filters, () -> Ux.Jooq.on(XModuleDao.class)
                .fetchOneAsync(filters)
                .compose(Ux::fnJObject)
                /* Metadata field usage */
                .compose(Ke.mount(KeField.METADATA)));
    }