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\" %> 

Throwable object describing the exception may be accessed within the error page via the exception implicit object.
Note: You must always use a relative URL as the value for the errorPage attribute.