www.ijecs.in International Journal Of Engineering And Computer Science Volume 8 Issue 5 May 2019, Page No. 24621-24628 ISSN: 2319-7242 DOI: 10.18535/ijecs/v8i05.4317 Ekwonwune Emmanuel N, IJECS Volume 8 Issue 5 May 2019 Page No. 24621-24628 Page 24621 Extracting Business Rule from existing COBOL programs for Redevelopment Ekwonwune Emmanuel N 1 and Egwuonwu Deborah I 2 1 Department of Computer Science, Imo State University, Owerri Nigeria 2 Department of Computer Science, Abia State Polytechnic, Aba, Nigeria Abstract The paper describes an industrial business study carried out to regain the business knowledge embedded in a legacy COBOL application. The aim of this work was to extract out the information required to re- implement the Legacy programs in a new client/server environment. The progress solution is in four step. Firstly, the programs were restructured, secondly the programs were sliced into business logic modules, third the business modules were subjected to a multi view analysis and finally the views were integrated into a unified documentation describing the data, decision and procedural flow of each program slice. Keywords: Reengineering, Reverse Engineering, Knowledge Extraction, Business Rules, Program Comprehension, Slicing 1. Introduction A legacy system is one which is extremely valuable to an organization, performing key strategic functions. But maintaining such systems as to incorporate new functionalities or due to organizational policy changes become hard in the absence of proper documentation, qualified staff and other resources. Due to the poor quality of the code, it is better to redevelop the application using modern object- oriented techniques and this called for creating a new functional specification and a new architectural design as it remain many black holes. Therefore if a description of the detailed business logic is to be recovered, then it must be recovered from the programs as the only reliable source of information. The cost of re-engineering a system is generally less than developing a new system. Sometimes what is required is, add some functionalities, change some policies, change the structure of system without changing functionalities, changing the architecture of the system to add some non functional requirements and for making these changes, it is worthless to develop a new system. Warren.[1999]. Stated that a legacy system is ―an old system which remains in operation within an organization‖ In the same year, Alderson et al. [1999] discussed two more definitions for legacy systems: ―any code that has left development‖ and ―a system whose security has been compromised‖. For many business-critical systems the problem was how to renovate the software system while at the same time business continued as usual. An often heard solution was to throw away the software as soon as a totally new system was finished; this ‘was sometimes called shadowing (Van den Brand et al., 2007). 2. Literature Review Chikofsky and Cross II [1990] stated that reverse engineering is ―the process of analysing a subject system to identify the system‘s components and their interrelationships and create representations of the system in another form or a higher level of abstractions‖