In JBoss 3.2.x when exception occurred, the HtmlAdaptor display the exception message.
In JBoss 4.0.x the HtmlAdaptor display only a generic error message.

This is obviously a regression. Can you add the message back?

Here is an example:
4.0.4:
javax.servlet.ServletException: Failed to invoke operation
org.jboss.jmx.adaptor.html.HtmlAdaptorServlet.invokeOp(HtmlAdaptorServlet.java:269)
org.jboss.jmx.adaptor.html.HtmlAdaptorServlet.processRequest(HtmlAdaptorServlet.java:100)
org.jboss.jmx.adaptor.html.HtmlAdaptorServlet.doPost(HtmlAdaptorServlet.java:82)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
root cause
javax.management.MBeanException
org.jboss.mx.interceptor.ReflectedDispatcher.handleInvocationExceptions(ReflectedDispatcher.java:180)
org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:163)
org.jboss.mx.server.Invocation.dispatch(Invocation.java:94)
org.jboss.mx.server.Invocation.invoke(Invocation.java:86)
org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264)
org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659)
org.jboss.jmx.adaptor.control.Server.invokeOpByName(Server.java:258)
org.jboss.jmx.adaptor.control.Server.invokeOp(Server.java:223)
org.jboss.jmx.adaptor.html.HtmlAdaptorServlet.invokeOp(HtmlAdaptorServlet.java:262)
org.jboss.jmx.adaptor.html.HtmlAdaptorServlet.processRequest(HtmlAdaptorServlet.java:100)
org.jboss.jmx.adaptor.html.HtmlAdaptorServlet.doPost(HtmlAdaptorServlet.java:82)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)

3.2.6:javax.servlet.ServletException: Failed to invoke operation
org.jboss.jmx.adaptor.html.HtmlAdaptorServlet.invokeOp(HtmlAdaptorServlet.java:248)
org.jboss.jmx.adaptor.html.HtmlAdaptorServlet.processRequest(HtmlAdaptorServlet.java:79)
org.jboss.jmx.adaptor.html.HtmlAdaptorServlet.doPost(HtmlAdaptorServlet.java:61)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:75)
root cause
MBeanException: com.koko.KOKOException: Invalid type
Cause: com.koko.KOKOException: Invalid type
org.jboss.mx.server.ReflectedDispatcher.handleInvocationExceptions(ReflectedDispatcher.java:91)
org.jboss.mx.server.ReflectedDispatcher.dispatch(ReflectedDispatcher.java:64)
org.jboss.mx.server.Invocation.dispatch(Invocation.java:62)
org.jboss.mx.server.Invocation.dispatch(Invocation.java:54)
org.jboss.mx.server.Invocation.invoke(Invocation.java:82)
org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:197)
org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:473)
org.jboss.jmx.adaptor.control.Server.invokeOpByName(Server.java:236)
org.jboss.jmx.adaptor.control.Server.invokeOp(Server.java:202)
org.jboss.jmx.adaptor.html.HtmlAdaptorServlet.invokeOp(HtmlAdaptorServlet.java:241)
org.jboss.jmx.adaptor.html.HtmlAdaptorServlet.processRequest(HtmlAdaptorServlet.java:79)
org.jboss.jmx.adaptor.html.HtmlAdaptorServlet.doPost(HtmlAdaptorServlet.java:61)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:75)