Could not find plugin class className – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch is unable to locate the specified plugin class. This could be due to the plugin not being installed, the class name being misspelled, or the plugin not being properly loaded. To resolve this issue, you can try installing the plugin if it’s not already installed, double-check the class name for any spelling errors, or ensure the plugin is correctly loaded by restarting Elasticsearch.

This guide will help you check for common problems that cause the log ” Could not find plugin class [” + className + “] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin, plugins.

Log Context

Log “Could not find plugin class [” + className + “]” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 private static Class loadPluginClass(String className; ClassLoader loader) {
 try {
 return Class.forName(className; false; loader).asSubclass(Plugin.class);
 } catch (ClassNotFoundException e) {
 throw new ElasticsearchException("Could not find plugin class [" + className + "]"; e);
 }  // package-private for testing
 static Plugin loadPlugin(Class pluginClass; Settings settings; Path configPath) {


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