1. A computer system for integrating existing source code into target source code, the computer system comprising: a processor; and a memory storing executable instructions for said processor to execute: a change point mapper that outputs a plurality of suggested candidate mappings between a change point of the existing source code and a plurality of change points of the target source code; a change point transformer that receives the plurality of suggested candidate mappings and outputs an updated existing source code, the change point transformer being configured to automatically update the existing source code based on a selected candidate mapping of the plurality of suggested candidate mappings; and a change point transplanter being configured to insert the updated existing source code into the target source code, wherein the existing source code comprises a plurality of change points including the change point, and for each change point of the plurality of change points of the existing source code, the change point mapper automatically identifies whether a candidate mapping exists between each change point of the existing source code and each change point of the plurality of change points of the target source code, and wherein, when the plurality of change points of the existing source code comprises a plurality of change points that share a suggested candidate mapping to one or more change points of the plurality of change points of the target source code, the change point mapper filters the plurality of suggested candidate mappings based on whether a change point of the plurality of change points that share candidate mappings to one or more change points of the plurality of change points of the target source code comprises a boundary change point.