title: Unable to create solr core
body: <p>I have a solr 5.2.1 instance and I want to create a new core named production.
  I had several issues with access rights which got solved, but the following exception is totally unclear to me. Help is appreciated.</p>
  
  <pre><code>org.apache.solr.common.SolrException: Error CREATEing SolrCore 'production': Unable to create core [production] Caused by: solr.JsonUpdateRequestHandler
      at org.apache.solr.handler.admin.CoreAdminHandler.handleCreateAction(CoreAdminHandler.java:661)
      at org.apache.solr.handler.admin.CoreAdminHandler.handleRequestInternal(CoreAdminHandler.java:213)
      at org.apache.solr.handler.admin.CoreAdminHandler.handleRequestBody(CoreAdminHandler.java:193)
      at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:143)
      at org.apache.solr.servlet.HttpSolrCall.handleAdminRequest(HttpSolrCall.java:660)
      at org.apache.solr.servlet.HttpSolrCall.call(HttpSolrCall.java:431)
      at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:227)
      at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:196)
      at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
      at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:585)
      at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
      at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:577)
      at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:223)
      at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1127)
      at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:515)
      at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
      at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1061)
      at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
      at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:215)
      at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:110)
      at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97)
      at org.eclipse.jetty.server.Server.handle(Server.java:497)
      at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:310)
      at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:257)
      at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:540)
      at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:635)
      at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:555)
      at java.lang.Thread.run(Thread.java:745)
  Caused by: org.apache.solr.common.SolrException: Unable to create core [production]
      at org.apache.solr.core.CoreContainer.create(CoreContainer.java:651)
      at org.apache.solr.core.CoreContainer.create(CoreContainer.java:611)
      at org.apache.solr.handler.admin.CoreAdminHandler.handleCreateAction(CoreAdminHandler.java:628)
      ... 27 more
  Caused by: org.apache.solr.common.SolrException: Error loading class 'solr.JsonUpdateRequestHandler'
      at org.apache.solr.core.SolrCore.&lt;init&gt;(SolrCore.java:815)
      at org.apache.solr.core.SolrCore.&lt;init&gt;(SolrCore.java:658)
      at org.apache.solr.core.CoreContainer.create(CoreContainer.java:637)
      ... 29 more
  Caused by: org.apache.solr.common.SolrException: Error loading class 'solr.JsonUpdateRequestHandler'
      at org.apache.solr.core.SolrResourceLoader.findClass(SolrResourceLoader.java:491)
      at org.apache.solr.core.SolrResourceLoader.findClass(SolrResourceLoader.java:422)
      at org.apache.solr.core.SolrCore.createInstance(SolrCore.java:566)
      at org.apache.solr.core.PluginBag.createPlugin(PluginBag.java:122)
      at org.apache.solr.core.PluginBag.init(PluginBag.java:217)
      at org.apache.solr.core.RequestHandlers.initHandlersFromConfig(RequestHandlers.java:130)
      at org.apache.solr.core.SolrCore.&lt;init&gt;(SolrCore.java:768)
      ... 31 more
  Caused by: java.lang.ClassNotFoundException: solr.JsonUpdateRequestHandler
      at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
      at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
      at java.net.FactoryURLClassLoader.loadClass(URLClassLoader.java:793)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
      at java.lang.Class.forName0(Native Method)
      at java.lang.Class.forName(Class.java:278)
      at org.apache.solr.core.SolrResourceLoader.findClass(SolrResourceLoader.java:475)
  </code></pre>