Mainframe
COBOL to Java, C#
& Cloud
A complete "big-bang" modernization is often too risky and complex for large mainframe systems. SoftwareMining provides a phased approach to modernization where COBOL modules are gradually converted to Java. Each module is translated, tested, and deployed to production while continuing to work alongside the remaining COBOL application.
This step-by-step strategy reduces project risk and allows early business value. Batch and online components are usually the easiest to isolate and modernize first. Additional stand-alone modules can be identified automatically using SoftwareMining's call-chain analysis, which groups related programs for translation and testing.
The result is a controlled migration process where newly generated Java components work seamlessly with the remaining COBOL code. Each iteration produces smaller, testable Java modules that can later replace mainframe dependencies such as VSAM, CICS, and legacy databases with standard SQL systems.
This incremental refactoring allows teams to modernize large COBOL applications safely while maintaining production stability.
Many enterprise platforms, including IBM systems, already support Java through native interfaces such as JCICS or SQL (for example, DB400). This means that accessing COBOL data from Java is straightforward as long as structure compatibility and encoding are managed carefully.
For every COBOL data structure, SoftwareMining automatically generates a Java Data Access Object (DAO) with matching fields. The translator monitors how each field is used and assigns the appropriate level of formatting or binary compatibility.
Binary-compatible DAOs are used when:
In other cases, native Java data types (for example, double or BigDecimal) are used. This improves performance while keeping data accuracy. COBOL compatibility is maintained when needed, and pure Java types are applied where possible.
Since Java DAOs are compatible with COBOL structures, they can exchange data directly with legacy files. IBM provides libraries such as JCICS that allow Java to read and write to the same VSAM or CICS-managed files used by COBOL.
This ensures that both COBOL and Java modules can share the same datasets until the migration to relational databases is complete.
The translator automatically converts embedded SQL statements in COBOL into equivalent Java or C# statements. The resulting Java application can communicate with DB2 or other SQL databases while coexisting with the original COBOL modules.
DAOs generated for DB400 or DB2 use standard SQL for data access, ensuring interoperability between both environments.
Many COBOL systems use IBM MQ for inter-program communication. The translated Java applications maintain this behavior using IBM MQ libraries.
The modernized Java applications can continue to use IBM MQ as the message transport layer, ensuring compatibility and stability.
Many COBOL programs use sequential files to store and retrieve data. The SoftwareMining translator generates matching DAOs and Java file readers/writers, allowing the new Java application to use the same files.
Over time, sequential storage can be replaced with relational or structured formats such as XML or JSON, enabling easier integration with APIs and web services.
COBOL and Java modules can communicate directly or through shared data layers.
The shared data-store approach is often preferred because it requires less custom code, is easier to scale, and allows gradual migration without disrupting production.
In the long term, organizations can migrate from VSAM or ISAM to relational databases. The translated Java application provides the foundation for this shift. SQL-based DAOs replace file-based storage, improving performance, integration, and maintainability.
This gradual transition ensures that modernization can proceed safely while preserving data integrity and existing business rules.