Author: sampath amatam

The enduring prevalence of COBOL (Common Business-Oriented Language) in mission-critical applications poses a challenge for modernization efforts, particularly in the transition to Java. This paper explores the intricacies of converting COBOL to Java, emphasizing the avoidance of JOBOL—a term coined for Java code that retains procedural characteristics without embracing object-oriented principles. The discussion includes strategies for data-oriented conversion, dead code elimination, and the adoption of event-driven approaches to ensure a successful transition that leverages the full potential of Java.

Introduction

COBOL, an acronym for Common Business-Oriented Language, has been a stalwart in the programming world, particularly for business applications, since its inception in the late 1950s. Despite its age, COBOL remains a critical component in many organizations, with millions of lines of code still in use for core mission-critical applications. However, as technology advances, there is an increasing push towards modernization, with Java being a popular target language due to its object-oriented nature, robust ecosystem, and wide adoption in contemporary software development.

The migration of mainframe application code and data to contemporary technologies represents a pivotal phase in the evolution of information technology systems, particularly in the pursuit of enhancing efficiency and scalability. This transition, which often involves shifting from legacy mainframe environments to more flexible cloud-based or on-premises solutions, is not merely a technical relocation of resources; it is a fundamental transformation that necessitates rigorous testing to ensure functionality equivalence. The objective is to ascertain those applications, once running on mainframe systems, maintain their operational integrity and performance standards when transferred to modernized platforms.

This process of migration is further complicated by the dynamic nature of business environments. Post-migration, applications frequently undergo numerous modifications driven by new requirements, evolving business strategies, or changes in regulatory standards. Each modification, whether it’s a minor adjustment or a major overhaul, must be meticulously tested. The critical challenge lies in ensuring that these new changes harmoniously integrate with the existing functionalities, without inducing unintended consequences or disruptions. This dual requirement of validating new features and safeguarding existing functionalities underscores the complexity of post-migration automation test suite maintenance.

The latest IBM mainframe model, the z16, is fully compatible with the original IBM 360, although many improvements have been made over the 60 years the product line has been in production.  Today, IBM mainframes host applications that run many of the world’s largest and most successful businesses. An estimated 10,000 mainframe systems are being used today for industries spanning banking, healthcare, insurance, retail, telecommunications, travel, and more. And mainframe applications are used to process credit card payments, stock trades, and other business-critical transactions. 

However, the cost of mainframe computing can be significant. As such, many modernization efforts are designed to reduce costs and modernize applications. These efforts can be aided using IBM Z mainframe specialty processors such as the IFL (Integrated Facility for Linux) and zIIP (System Z Integrated Information Processor). Workloads that run on these processors are less expensive than those that run on traditional IBM Z general-purpose processors.