How does JSP handle run-time exceptions?

You can use the errorPage attribute of the page directive to have uncaught run-time exceptions automatically forwarded to an error processing page.

For example: 

<%@ page errorPage="error.jsp" %> 

redirects the browser to the JSP page error.jsp if an uncaught exception is encountered during request processing. Within error.jsp, if you indicate that it is an error-processing page, via the directive:

<%@ page isErrorPage="true" %>

In the error pages we can access exception implicit object.