Migrating AS400-COBOL to Java: A Report from the Field

This paper describes an industrial project aimed at migrating legacy COBOL programs running on an IBM-AS400 to Java for running in an open environment. The unique aspect of this migration is the reengineering of the COBOL code prior to migration. The programs were in their previous form hardwired to the AS400 screens as well as to the AS400 file system. The goal of the reengineering project was to free the code from these proprietary dependencies and to reduce them to the pure business logic. Disentangling legacy code from it´s physical environment is a major prerequisite to converting that code to another environment. The goal is the virtualization of program interfaces. That was accomplished here in a multistep automated process which led to small, environment independent COBOL modules which could be readily converted over into Java packages. The pilot project has been completed for a sample subset of the production planning and control system. The conversion to Java is pending the test of the reengineered COBOL modules.