Remodularizing Java programs for improved locality of feature implementations in source code

Explicit traceability between features and source code is known to help programmers to understand and modify programs during maintenance tasks. However, the complex relations between features and their implementations are not evident from the source code of object-oriented Java programs. Consequently, the implementations of individual features are difficult to locate, comprehend, and modify in isolation. In this paper, we present a novel remodularization approach that improves the representation of features in the source code of Java programs. Both forward and reverse restructurings are supported through on-demand bidirectional restructuring between feature-oriented and object-oriented decompositions. The approach includes a feature location phase based on tracing of program execution, a feature representation phase that reallocates classes into a new package structure based on single-feature and multi-feature packages, and an annotation-based reverse transformation of code. Case studies performed on two open-source projects indicate that our approach requires relatively little manual effort and reduces tangling and scattering of feature implementations in the source code.