title: How to use "jython-standalone-2.7-b3.jar" in windows 7?
body: <p>I want to upgrade Jython from "jython2.5.4rc1" to "Jython 2.7-beta3".</p>
  
  <p>I have downloaded following two files from "<a href="http://www.jython.org/downloads.html" rel="nofollow">http://www.jython.org/downloads.html</a>":</p>
  
  <pre><code>1. Jython 2.7beta3 - Installer      - jython-installer-2.7-b3.jar
  2. Jython 2.7beta3 - Standalone Jar - jython-standalone-2.7-b3.jar
  </code></pre>
  
  <p>When I doubleclick on "jython-installer-2.7-b3.jar" file, I am getting "Could n ot find the main class:org.python.util.install.Installation.program will exit" error.</p>
  
  <p>Then I tried by using following command , But I am getting same error:</p>
  
  <pre><code>C:\Users\Downloads&gt;java -jar jython-standalone-2.7-b3.jar
  Exception in thread "main" java.lang.UnsupportedClassVersionError: org/python/util/jython : Unsupported major.minor version 51.0
      at java.lang.ClassLoader.defineClass1(Native Method)
      at java.lang.ClassLoader.defineClassCond(Unknown Source)
      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$000(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)
  Could not find the main class: org.python.util.jython. Program will exit.
  </code></pre>
  
  <p>C:\Users\Downloads></p>
  
  <p>I tried both Installer and standalone jar files using the above command. Its throws same error.</p>
  
  <p>Could anyone please guide me on How to install this "jython-installer-2.7-b3.jar" file</p>
  
  <p>Thanks in advance.</p>