Constructs a new JSP exception when the JSP
needs to throw an exception and include a message
about the "root cause" exception that interfered with its
normal operation. The exception's message is based on the localized
message of the underlying exception.
This method calls the
Throwable exception to get a localized exception
message. When subclassing
this method can be overridden to create an exception message
designed for a specific locale.
this.rootCause = rootCause;