ClassCastException occurs in my web app, because classloaders load the same class twice, when two web apps share WebLogic wlfullclient.jar. Any idea how to avoid that? Details below.
Project set-up: - Tomcat 6.0.13 + Weblogic 10.0 - wlfullclient.jar is placed in <TOMCAT_HOME>\lib. - two web apps are deployed on Tomcat (WebApp1 & WebApp2). The wep apps don't share any libraries except wlfullclient.jar. - both web apps are subscribed to weblogic JMS topic. Error scenario: 1. a message is generated in the weblogic JMS topic 2. both web apps retrieve the message 3. logic that handles the message in WepApp2 operates on a certain class that belongs to WebApp2 (let's call the class "XXX" for convenience). Namely, the logic contains casting: Object xxxObject = someJndiLookup(); XXX someVariable = (XXX) xxxObject; 4. Casting results in ClassCastException. Debugging shows that xxxObject is an object of the XXX class and its loaded by WebLogic GenericClassLoader. And the object is cast to the XXX class loaded by WebApp2ClassLoader. Reason: At the server startup, WebLogic GenericClassLoader (that is provided within wlfullclient.jar) is loaded and it sets WepApp1ClassLoader as its parent. XXX class is a part of WepApp2 and obviously is loaded by WepApp2ClassLoader. When Weblogic JMS message comes up, GenericClassLoader has to deal with an object of the XXX class. According to the classloaders delegation model GenericClassLoader first asks its parent whether the parent knows XXX. But - surprise - the parent of GenericClassLoader is WepApp1ClassLoader. Obviously WepApp1ClassLoader does not know this class, since it belongs to WebApp2. That's why GenericClassLoader decides to load the class itself. As a result there are multiple copies of the same class. --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
