title: Neo4j Server issue: "Could not find the main class: org.neo4j.server.storemigration.PreStartupStoreUpgrader. Program will exit."
body: <p>I have used the Neo4j database successfully on my Ubuntu 12.04 before I moved on Mint 13. So, I installed the database (as described <a href="http://docs.neo4j.org/chunked/stable/server-installation.html" rel="nofollow">here</a>) and tried to start neo4j-service:</p>
  
  <pre><code>sudo service neo4j-service start
  </code></pre>
  
  <p>Every time I try to start I see this:</p>
  
  <pre><code>WARNING: Max 1024 open files allowed, minimum of 40 000 recommended. See the Neo4j manual.
  WARNING! You are using an unsupported Java runtime. Please use JDK 6.
  Starting Neo4j Server...Exception in thread "main" java.lang.NoClassDefFoundError: org/neo4j/server/storemigration/PreStartupStoreUpgrader
  Caused by: java.lang.ClassNotFoundException: org.neo4j.server.storemigration.PreStartupStoreUpgrader
      at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
      at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
  Could not find the main class: org.neo4j.server.storemigration.PreStartupStoreUpgrader. Program will exit.
  </code></pre>
  
  <p>Here are the results of <code>java -version</code> command:</p>
  
  <pre><code>java version "1.6.0_24"
  OpenJDK Runtime Environment (IcedTea6 1.11.5) (6b24-1.11.5-0ubuntu1~12.04.1)
  OpenJDK 64-Bit Server VM (build 20.0-b12, mixed mode)
  </code></pre>
  
  <p>I run Linux Mint 13 Cinnamon x86_64. As I said, everything was alright on Ubuntu 12.04 x86_64 with the same version of OpenJDK.</p>
  
  <p>What should I do? Thank you. </p>