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

Opster Team

August-23, Version: 6.8-7.15

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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.

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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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