title: Class file don't run
body: <pre><code>C:\Users\student3&gt;java -cp C:\users\student3 start
  Exception in thread "main" java.lang.NoClassDefFoundError: start (wrong name: wo
  rk/start)
          at java.lang.ClassLoader.defineClass1(Native Method)
          at java.lang.ClassLoader.defineClass(Unknown Source)
          at java.security.SecureClassLoader.defineClass(Unknown Source)
          at java.net.URLClassLoader.defineClass(Unknown Source)
          at java.net.URLClassLoader.access$100(Unknown Source)
          at java.net.URLClassLoader$1.run(Unknown Source)
          at java.net.URLClassLoader$1.run(Unknown Source)
          at java.security.AccessController.doPrivileged(Native Method)
          at java.net.URLClassLoader.findClass(Unknown Source)
          at java.lang.ClassLoader.loadClass(Unknown Source)
          at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
          at java.lang.ClassLoader.loadClass(Unknown Source)
          at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)
  </code></pre>
  
  <p>screenshot: <a href="http://imageshack.us/photo/my-images/835/mt6a.png/" rel="nofollow">http://imageshack.us/photo/my-images/835/mt6a.png/</a>
  It's my first run class by windows, what happens?</p>
  
  <p><strong>UPDATE:</strong></p>
  
  <p>Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/poi/ss/usermodel/Row so.. should i create 1 hundred directories? </p>