IBM offers just such a service under the WatsonX branding, it's an LLM to convert COBOL to Java: https://www.ibm.com/products/watsonx-code-assistant-z
I work at a company with a large COBOL codebase and this has been mentioned in a few presentations about our modernization efforts.
But is the conversion maintainable by a human? I’ve seen Fortran to C translators that end up encoding state transition machines that are impossible to read.
How did that go? My employer is going to try snd evaluate watsonx product. Have you had any luck converting large/complex COBOL modules ?
You should take a look at my company. Heirloom Computing. Heirloom.cc We have migrated many mainframe application and millions of lines of cobol and pl1 into Java and deployed it into production on prem and into the cloud.