There appears to be a bug in 2.4.1, where the "assigned to me" portlet on the dashboard triggers this exception:

org.apache.jasper.JasperException: For input string: "null"
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:254)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:684)
at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:575)
at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:498)
at org.apache.jasper.runtime.JspRuntimeLibrary.include(JspRuntimeLibrary.java:822)
at org.apache.jsp.dashboard_jsp._jspService(dashboard_jsp.java:417)

In the atlassian-jira-.*.log file, more detail is provided:

----- Root Cause -----
java.lang.NumberFormatException: null
at java.lang.Integer.parseInt(Integer.java:426)
at java.lang.Integer.parseInt(Integer.java:476)
at org.apache.jsp.assignedissues_jsp._jspService(assignedissues_jsp.java:113)
....

This is due to a bug in the upgrade process. The fix is to copy the attached assignedissues.jsp file to either:

• atlassian-jira/includes/dashboard/assignedissues.jsp in the standalone distribution
• webapp/includes/dashboard/assignedissues.jsp in the webapp distribution