I saw some old thread about caching the rule base on your own.  I have a singleton which contains a hashmap to do the caching.  I am using the Guvnor to pull my rules from.  This works fine except when the rules change on the Guvnor.  When the rule base tries to refresh in my application, I am getting a ClassCastException.  Any ideas? 
 
RuleAgent(Assembly) EXCEPTION (Fri Feb 26 12:02:32 EST 2010): java.lang.ClassCastException: org.drools.util.ObjectHashMap cannot be cast to org.drools.reteoo.BetaMemory. Stack trace should follow.
org.drools.RuntimeDroolsException: java.lang.ClassCastException: org.drools.util.ObjectHashMap cannot be cast to org.drools.reteoo.BetaMemory
 
My code to do the caching is below:
 
private HashMap<String, RuleBase> ruleBaseMap = new HashMap<String, RuleBase>();
  // check to see if we already set up this rule base

  if (ruleBaseMap.containsKey(product.getConfigurationRule())) {
   rb = ruleBaseMap.get(product.getConfigurationRule());
  } else {
   
   try {
    InitialContext context = new InitialContext();
    url = (String) context.lookup("java:comp/env/rules.url");
    url = url + product.getConfigurationRule() + "/LATEST";
   } catch (NamingException e1) {
   }
   
   Properties config = new Properties();
   config.setProperty("newInstance", "false");
   config.setProperty("url", url);
   config.setProperty("poll", "300");
   config.setProperty("name", "Assembly");
   RuleAgent agent = RuleAgent.newRuleAgent(config);
   rb = agent.getRuleBase(); 
   
   ruleBaseMap.put(product.getConfigurationRule(), rb);
  }