Errors are not handled correctly in UIPortletActionListener.handleErrorResponse ------------------------------------------------------------------------------- Key: GTNPORTAL-3122 URL: https://issues.jboss.org/browse/GTNPORTAL-3122 Project: GateIn Portal Issue Type: Bug Security Level: Public(Everyone can see) Components: WebUI Affects Versions: 3.6.0.Beta02 Reporter: Martin Weiler Attachments: reproducer-for-GTNPORTAL-3122.zip When a portlet is running into a NoClassDefFoundError in processAction method, this error is not handled properly in UIPortletActionListener.handleErrorResponse: {code:title=UIPortletActionListener.java|borderStyle=solid} private void handleErrorResponse(ErrorResponse response) throws Exception { throw (Exception) response.getCause(); } {code} This code tries to cast the Throwable to Exception, resulting in a ClassCastException which hides the real error. As a result, it is not possible to see the root cause of the issue in the log file.