title: Exception class jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to class java.net.URLClassLoader
body: <p>I don't understand how to fix it, first time i see mistake like this.
  i downland this from github <a href="https://github.com/nikishubin/Notebook" rel="nofollow noreferrer">https://github.com/nikishubin/Notebook</a> but its does not work</p>
  <pre><code>OpenJDK 64-Bit Server VM warning: Options -Xverify:none and -noverify were deprecated in JDK 13 and will likely be removed in a future release.
      Exception in thread &quot;main&quot; java.lang.ClassCastException: class jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to class java.net.URLClassLoader (jdk.internal.loader.ClassLoaders$AppClassLoader and java.net.URLClassLoader are in module java.base of loader 'bootstrap')
          at org.springframework.boot.devtools.restart.DefaultRestartInitializer.getUrls(DefaultRestartInitializer.java:93)
          at org.springframework.boot.devtools.restart.DefaultRestartInitializer.getInitialUrls(DefaultRestartInitializer.java:56)
          at org.springframework.boot.devtools.restart.Restarter.&lt;init&gt;(Restarter.java:140)
          at org.springframework.boot.devtools.restart.Restarter.initialize(Restarter.java:546)
          at org.springframework.boot.devtools.restart.RestartApplicationListener.onApplicationStartingEvent(RestartApplicationListener.java:67)
          at org.springframework.boot.devtools.restart.RestartApplicationListener.onApplicationEvent(RestartApplicationListener.java:45)
          at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172)
          at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165)
          at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139)
          at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:122)
          at org.springframework.boot.context.event.EventPublishingRunListener.starting(EventPublishingRunListener.java:69)
          at org.springframework.boot.SpringApplicationRunListeners.starting(SpringApplicationRunListeners.java:48)
          at org.springframework.boot.SpringApplication.run(SpringApplication.java:292)
          at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118)
          at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107)
          at org.surplus.radolf.Notebook.NotebookApplication.main(NotebookApplication.java:10)
      
      Process finished with exit code 1
  </code></pre>
  <p>my main class</p>
  <pre><code>package org.surplus.radolf.Notebook;
  
  import org.springframework.boot.SpringApplication;
  import org.springframework.boot.autoconfigure.SpringBootApplication;
  
  
  @SpringBootApplication
  public class NotebookApplication  {
      public static void main(String[] args) {
          SpringApplication.run(NotebookApplication.class, args);
      }
  }
  </code></pre>