It all depends where the Java and the COBOL programs live. We call IBM mainframe CICS COBOL from distributed systems via MQ-Series and COBOL stored procs via DirectConnect. I don't think we've pursued pure JCA solutions. Many vendors have products in this space like Attachmate Verastream.
You can run your Java on the mainframe, too. I have no hands on experience but IBM would love to show you how to run Linux and WebSphere under Z-OS, and I'm sure you could get Java and COBOL talking in other ways.
A good question is never answered. It is not a bolt to be tightened into place but a seed to be planted and to bear more seed toward the hope of greening the landscape of the idea. John Ciardi
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