The capability to evolve an application dynamically consists in activating new portions of code while the application runs. This can be considered particularly useful when applications need to adapt to fluctuating conditions of their environment. This paper aims at providing a general infrastructure that allows object-oriented applications to dynamically modify the way they work, without stopping. This infrastructure has a twofold objective: deciding which application activities best fit the current conditions, e.g. to exploit the increased availability or loss of resources; taking into account that new classes could have been developed and force the application to incorporate them while it runs. Computational reflection is used as a means to connect the proposed infrastructure with applications, for its interception mechanism provides the ability to intervene into the application operations in order to seamlessly introduce the desired changes.