Interfacing RASCAL with Java APIs and reusing existing implementations is a required functionality in order to reduce effort and time in contrast with implementing a new one from scratch. In this study we are trying to interface RASCAL with Apache POI, a Java implemented API in order to import and analyse Microsoft Oce les in RASCAL environment. Our focus is to describe the dierences between the data structures and types between the two programming paradigms, object oriented and functional, and to establish a mapping between the corresponding values. We investigated the possibility to automatically generate the mappings by performing a static source code analysis, and from the result of our analysis we generated the required source code in order to establish the communication between RASCAL and Apache POI. Also, we performed a validation of our approach by replicating one study where we achieved to perform equally or even better results.