title: Using java.util.prefs.Preferences in Jython
body: <p>I seem to be having trouble storing Java preferences using a Jython script. If in Jython 2.5 beta I use:</p>
  
  <pre><code>clazz = Class.forName('mypackage.myclass')
  prefs = Preferences.userNodeForPackage(clazz);
  # or Preferences.userRoot()
  prefs.put('propertyname', 'yes')
  </code></pre>
  
  <p>The preferences are not stored. If I then add:</p>
  
  <pre><code>prefs.flush()
  </code></pre>
  
  <p>I get</p>
  
  <blockquote>
    <p>java.util.prefs.BackingStoreException: Couldn't get file lock.</p>
  </blockquote>
  
  <p>I am currently running this on Linux and Unix using Java 1.6. I'm hoping that I'm missing something obvious, since my Java applications can successfully use java.util.prefs.Preferences on the same system.</p>
  
  <p>Any help would be greatly appreciated.</p>