In the world of programming languages, two giants have stood the test of time: COBOL and Java. While Java has become the go-to language for modern web development, COBOL continues to power critical systems in industries such as finance and healthcare.

This article will delve into the technical differences between COBOL and Java, bridging the gap for readers familiar with Java but less experienced with COBOL. Much of this article is basic and designed to highlight the differences between them so you can begin approaching a COBOL to Java conversion with a foundational understanding of what makes them different.

So, let’s crack the code and explore the nuances of these two languages.

Syntax: A Tale of Two Worlds

One of the most significant differences between COBOL and Java lies in their syntax. Java is known for its C-like syntax, making it more intuitive and familiar to programmers coming from languages like C++ or C#. On the other hand, COBOL has a unique syntax that sets it apart from most modern programming languages.

COBOL employs a business-oriented syntax designed for readability and clarity. It utilizes English-like statements and keywords, making it highly readable for non-programmers as well.

For example, in COBOL, a simple program to display “Hello, World!” would look like this:

IDENTIFICATION DIVISION.
PROGRAM-ID. HELLO-WORLD.
PROCEDURE DIVISION.
DISPLAY 'Hello, World!'.
STOP RUN.

In contrast, Java follows a more traditional approach with its syntax, using curly braces and semicolons to structure code blocks and statements.

The equivalent “Hello, World!” program in Java would be:

public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, World!");
}
}

Data Structures: The Building Blocks of Code

When it comes to data structures, both COBOL and Java offer powerful options, albeit with different approaches. COBOL is renowned for its support of fixed-length records, making it an ideal choice for processing large volumes of structured data. It provides extensive support for working with databases and files, utilizing hierarchical and indexed file structures.

Java, being a more modern language, offers a wide range of data structures out of the box. From arrays and lists to maps and sets, Java provides developers with flexible tools for managing and manipulating data. Additionally, Java’s object-oriented nature enables the creation of complex data structures through classes and inheritance.

For example, let’s consider the simple task of storing employee information. In COBOL, a record layout would define the structure of an employee:

01 EMPLOYEE-RECORD.
05 EMPLOYEE-ID PIC X(10).
05 EMPLOYEE-NAME PIC X(30).
05 EMPLOYEE-AGE PIC 9(2).

In Java, we could achieve the same using objects and classes:

public class Employee {
private String id;
private String name;
private int age;
// Constructor, getters, and setters omitted for brevity
}

Object-Oriented Programming: Unifying Paradigms

While COBOL predates the advent of object-oriented programming (OOP), Java embraced this paradigm from its inception. OOP is a robust methodology for designing and organizing code, enabling modular, reusable, and extensible software development.

COBOL, however, follows a more procedural programming approach. It focuses on step-by-step instructions and modularization through sections and paragraphs. Although COBOL lacks direct support for OOP, it can still achieve some level of modularity through the use of copybooks and subprograms.

Java, on the other hand, fully embraces OOP principles. It allows encapsulation, inheritance, and polymorphism, facilitating the creation of robust and scalable applications. Object-oriented concepts are at the core of Java’s class-based structure, making it an ideal language for building complex systems.

Bridging the Gap: Similarities and Transferable Skills

Despite their distinct differences, COBOL and Java share some common ground. Both languages prioritize readability and maintainability, albeit through different approaches. Additionally, both languages have extensive libraries and frameworks that simplify development and enhance functionality.

Fortunately, Java developers looking to venture into the world of COBOL can transfer a good chunk of their skill sets. Concepts like problem-solving, logic, and algorithmic thinking are universal across programming languages. Understanding basic data structures, control flow, and modularization principles will also help you grasp how COBOL is structured.

An important note to consider before you dig in, if you decide to do so: modern COBOL dialects, such as Micro Focus COBOL, offer integration with Java through interoperability mechanisms. This is a good thing. This allows COBOL programs to call Java methods and vice versa, enabling seamless integration between legacy COBOL systems and modern Java applications. The downside: results often fall short of real Java, and these constructs can lock you into one vendor and its technology.

Final Thoughts

This article explored the technical differences between COBOL and Java, bridging the gap for Java developers seeking to understand COBOL. From syntax and data structures to OOP principles and interoperability, we touched on key concepts that will help readers understand the nuances of these two languages.

However, mastering a programming language is not just about learning the syntax or understanding the technical details — it’s also a matter of developing proficiency through practice and experience. So be sure to roll up your sleeves and get coding! After all, the best way to learn is by doing.

CM First Group Can Help

Our deep experience with legacy enterprise systems puts us in a unique position to help reinvent your modernization efforts and set the stage for COBOL to Java conversions that can transform your organization.
Please contact us for more information or to schedule a demonstration of our CM evolveIT software and how its impact analysis capabilities can set your COBOL to Java project up for long-term success.

You can also call us at 888-866-6179 or email us at info@cmfirstgroup.com.