Deploying large-scale sensor networks involves the programming of many devices based on a desired mission. Techniques for reprogramming devices in situ have been investigated to mitigate the effort required when program updates are required or when the mission of the system changes. We consider a technique that is intended to support multiple concurrent missions by the system by exploiting available resources of the sensor network. In essence, our model is based on a tasking scheme, a common framework for the interchange and instantiation of tasks on multiple devices, and the use of attributes defining the resources in the system. A prototype system has been implemented to demonstrate and validate the concepts using the Imote2, a 32-bit mote architecture that has been configured with embedded Linux enabled with Java. Several applications have been rendered as tasks that are injected into a multi-node sensor network. Results demonstrate the support of concurrent overlaid applications in the system permitting task injection, maintenance, and termination. Performance evaluation of the scheme indicates benefits over an epidemic model of code dissemination.