Expected an object but found token – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

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Briefly, this error occurs when Elasticsearch expects a JSON object but encounters a different data type, such as an array or a string. This usually happens when the input data is not properly formatted. To resolve this issue, you can: 1) Check the structure of your input data and ensure it matches the expected format. 2) Validate your JSON data using a JSON validator. 3) Review your Elasticsearch query to ensure it’s correctly structured. 4) If you’re using a client library, ensure it’s correctly serializing your data into a JSON object.

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This guide will help you check for common problems that cause the log ” expected an object; but found token [{}] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin.

Log Context

Log “expected an object; but found token [{}]” class name is XContentUtils.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 if (parser.currentToken() == XContentParser.Token.START_OBJECT) {
 XContentParser.Token token = parser.nextToken();
 if (token != XContentParser.Token.START_OBJECT) {
 throw new ElasticsearchParseException("expected an object; but found token [{}]"; parser.currentToken());
 }  public static String[] readStringArray(XContentParser parser; boolean allowNull) throws IOException {
 if (parser.currentToken() == XContentParser.Token.VALUE_NULL) {


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