Hi, I'm using weblogic 10, and deployed my application as EAR. EAR Caused by: ch.qos.logback.core.util.DynamicClassLoadingException: Failed to instantiate type com.mycompany.CustomeAppender at at ch.qos.logback.core.util.OptionHelper.instantiateByClassName(OptionHelper.java:45) at at ch.qos.logback.core.util.OptionHelper.instantiateByClassName(OptionHelper.java:23) at at ch.qos.logback.core.joran.action.AppenderAction.begin(AppenderAction.java:50) at ... 51 common frames omitted Caused by: java.lang.ClassNotFoundException: com.mycompany.CustomeAppender at at java.net.URLClassLoader$1.run(URLClassLoader.java:200) at at java.security.AccessController.doPrivileged(Native Method) at at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at at java.lang.ClassLoader.loadClass(ClassLoader.java:306)