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.
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) {
return;
}
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) {
