The following lines in o.a.p.b.frameworks.spring.PortletApplicationModelImpl has throws ClassCastException:
PropertyValue value = bd.getPropertyValues().getPropertyValue("lookupKey");
if (value != null)
lookup = (String)value.getValue(); // ClassCastException here: getValue does not return String object any more.
I found this problem when I tried to integrate a customized j2-admin's PortalSiteDetails portlet with Jetspeed-2.1.2.
The portlet is customized from the old j2-admin::SiteDetailsPortlet, which is out-of-date in Jetspeed-2.1.2.
Anyway, this problem can occur when a portlet utilizes framework bridge.