[jimueller]

This response is less on Java and more on the author's opinion of mainframes.

Large companies are risk adverse and generally for a good reason. That mainframe running COBOL has probably been reliably processing orders, crunching financials, and managing inventory for 30 years. No one is going to replace that on a whim because COBOL isn't cool. What are they going to use instead? It's certainly not Mongo DB and Lua scripts on AWS. SAP possibly, but you still end up with an expensive system with even more unpredictable cost and licensing terms.