Writing custom lists of maps

6091 [I/O dispatcher 1] ERROR l.t.c.e.ElasticConnection - Bulk item failure: '{"index":"docs","type":"doc","id":"url0","cause":{"type":"exception","reason":"Elasticsearch exception [type=mapper_parsing_exception, reason=object mapping for [entities] tried to parse field [entities] as object, but found a concrete value]"},"status":400}' for request 'org.elasticsearch.action.update.UpdateRequest@1f62f8da'