Unexpected token token expected – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch encounters an unexpected token in the JSON request body. It expects a “{” to start an object but finds a different token. This usually happens due to incorrect JSON syntax. To resolve this issue, you can validate your JSON request body for any syntax errors. Make sure that all objects start with “{” and end with “}”. Also, ensure that all strings are enclosed in double quotes and that commas are used correctly to separate key-value pairs within objects.

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

Log Context

Log “unexpected token [” + token + “]; expected [{]” class name is StoredScriptSource.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 .createParser(XContentParserConfiguration.EMPTY.withDeprecationHandler(LoggingDeprecationHandler.INSTANCE); stream)
 ) {
 Token token = parser.nextToken();  if (token != Token.START_OBJECT) {
 throw new ParsingException(parser.getTokenLocation(); "unexpected token [" + token + "]; expected [{]");
 }  token = parser.nextToken();  if (token != Token.FIELD_NAME) {


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