Abstract: This paper proposes a novel methodology for enabling
debugging and tracing of production web applications without
affecting its normal flow and functionality. This method of debugging
enables developers and maintenance engineers to replace a set of
existing resources such as images, server side scripts, cascading
style sheets with another set of resources per web session. The new
resources will only be active in the debug session and other sessions
will not be affected. This methodology will help developers in tracing
defects, especially those that appear only in production environments
and in exploring the behaviour of the system. A realization of the
proposed methodology has been implemented in Java.