Template must not be null – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch tries to create or update an index template but the template provided is null or empty. This could be due to a programming error or incorrect API usage. To resolve this issue, ensure that the template you’re trying to create or update is correctly defined and not null. Check your code or API call to make sure you’re passing a valid template. If you’re using a file to define the template, ensure the file exists and is correctly formatted.

This guide will help you check for common problems that cause the log ” Template must not be null ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin, template.

Log Context

Log “Template must not be null” class name is TemplateUtils.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 * Parses and validates that the source is not empty.
 public static void validate(String source) {
 if (source == null) {
 throw new ElasticsearchParseException("Template must not be null");
 if (Strings.isEmpty(source)) {
 throw new ElasticsearchParseException("Template must not be empty");