Expected XContentParser Token START OBJECT under – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-7.15

Briefly, this error occurs when Elasticsearch expects a JSON object (indicated by XContentParser.Token.START_OBJECT) but doesn’t find it under a specific field. This could be due to incorrect JSON formatting or a missing opening brace ‘{‘. To resolve this issue, you can: 1) Check the JSON input for correct formatting and ensure all objects start with ‘{‘. 2) Validate your JSON using a tool to find any syntax errors. 3) Review your Elasticsearch query to ensure it’s correctly structured and matches the expected format.

This guide will help you check for common problems that cause the log ” Expected [” + XContentParser.Token.START_OBJECT + “] under [ ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: parser, aggregations, search.

Log Context

Log “Expected [” + XContentParser.Token.START_OBJECT + “] under [” class name is AggregatorFactories.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 SuggestingErrorOnUnknown.suggest(fieldName; ex.getCandidates()));
 throw new ParsingException(new XContentLocation(ex.getLineNumber(); ex.getColumnNumber()); message; ex);
 } else {
 throw new ParsingException(parser.getTokenLocation(); "Expected [" + XContentParser.Token.START_OBJECT + "] under ["
 + fieldName + "]; but got a [" + token + "] in [" + aggregationName + "]");
 }  if (aggBuilder == null) {


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