The execution of job flow applications is a reality today in academic and industrial domains. In this paper, we propose an approach to adding self-healing behavior to the execution of job flows without the need to modify the job flow engines or redevelop the job flows themselves. We show the feasibility of our non-intrusive approach to self-healing by inserting a generic proxy to an existing two-level job-flow management system, which employs job flow based service orchestration at the upper level, and service choreography at the lower level. The generic proxy is inserted transparently between these two layers so that it can intercept all their interactions. We developed a prototype of our approach in a real Grid environment to show how the proxy facilitates runtime handling for failure recovery.