title: Failed to start ElasticSearch - Could not find plugin class
body: <p>We have an existing java based custom plugin for ElasticSearch. We now upgraded to ElasticSearch 2.1.1 and added plugin-descriptor.properties files to point to our plugin class.</p>
  
  <p>After that, we were able to install our custom plugin. But when we start ElasticSearch service, it is unable to find this custom plugin. We verified that the class file is present under the /usr/share/elasticsearch/plugins/ directory.</p>
  
  <p>Following is the exception stack trace:</p>
  
  <pre><code>[2016-01-20 13:13:48,527][ERROR][bootstrap] Exception
  ElasticsearchException[Could not find plugin class [com.symc.edp.elasticsearch.plugin.CustomEDPPlugins]]; nested: ClassNotFoundException[com.symc.edp.elasticsearch.plugin.CustomEDPPlugins];
          at org.elasticsearch.plugins.PluginsService.loadPluginClass(PluginsService.java:382)
          at org.elasticsearch.plugins.PluginsService.loadBundles(PluginsService.java:348)
          at org.elasticsearch.plugins.PluginsService.&lt;init&gt;(PluginsService.java:109)
          at org.elasticsearch.node.Node.&lt;init&gt;(Node.java:146)
          at org.elasticsearch.node.Node.&lt;init&gt;(Node.java:128)
          at org.elasticsearch.node.NodeBuilder.build(NodeBuilder.java:145)
          at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:178)
          at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:285)
          at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:35)
  Caused by: java.lang.ClassNotFoundException: com.symc.edp.elasticsearch.plugin.CustomEDPPlugins
          at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
          at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
          at java.net.FactoryURLClassLoader.loadClass(URLClassLoader.java:814)
          at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
          at org.elasticsearch.plugins.PluginsService.loadPluginClass(PluginsService.java:380)
          ... 8 more
  [2016-01-20 13:22:55,236][INFO ][node                     ] [localhost] version[2.1.1], pid[20680], build[40e2c53/2015-12-15T13:05:55Z]
  [2016-01-20 13:22:55,237][INFO ][node                     ] [localhost] initializing ...
  [2016-01-20 13:22:55,840][ERROR][bootstrap                ] Exception
  ElasticsearchException[Could not find plugin class [com.symc.edp.elasticsearch.plugin.CustomEDPPlugins.class]]; nested: ClassNotFoundException[com.symc.edp.elasticsearch.plugin.CustomEDPPlugins.class];
          at org.elasticsearch.plugins.PluginsService.loadPluginClass(PluginsService.java:382)
          at org.elasticsearch.plugins.PluginsService.loadBundles(PluginsService.java:348)
          at org.elasticsearch.plugins.PluginsService.&lt;init&gt;(PluginsService.java:109)
          at org.elasticsearch.node.Node.&lt;init&gt;(Node.java:146)
          at org.elasticsearch.node.Node.&lt;init&gt;(Node.java:128)
          at org.elasticsearch.node.NodeBuilder.build(NodeBuilder.java:145)
          at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:178)
          at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:285)
          at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:35)
  Caused by: java.lang.ClassNotFoundException: com.symc.edp.elasticsearch.plugin.CustomEDPPlugins.class
          at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
          at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
          at java.net.FactoryURLClassLoader.loadClass(URLClassLoader.java:814)
          at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
          at org.elasticsearch.plugins.PluginsService.loadPluginClass(PluginsService.java:380)
          ... 8 more
  </code></pre>
  
  <p>Following is the content of our plugin-descriptor.properties</p>
  
  <pre><code>description=EDP Custom Plugins
  version=${project.version}
  name=edpCustomPlugins
  jvm=true
  site=false
  classname=com.symc.edp.elasticsearch.plugin.CustomEDPPlugins
  java.version=${java.specification.version}
  elasticsearch.version=2.1.1
  </code></pre>