Ok. I'm not familiar with that tool, other than what they have to say on their website, and it does not appear that they are a "COBOL to Java Bytecode" compiler, rather they seek to "compile" your COBOL programs into Java which can then be run on a JVM on any platform. While not stated outright, I infer from their website that they provide a set of connectors to get to your Db2/VSAM data (this would be thought of as "lock-in" to their product) from your newly created Java programs.
There are significant differences in the approach taken to writing COBOL programs (top/down, structured) compared to writing Java programs (class based, object oriented), so I am wondering what sort of programs are emitted in Java and if an experienced Java programmer would want to deal with a Java program that was built/structured like a COBOL program. Or, perhaps they provide a level of expertise to guide the code conversion into a set of classes, constructors and functional programs - a more sustainable approach.
If the goal is to get to zIIPs, I'd suggest an approach that goes after a small part of the COBOL application at a time - you can do the "conversion" yourself or use tools. I write about such an approach here:
Mainframe MIPS: Management or Madness.
If you find out more, I think there are many in this community who would be interested in understanding the process and what the outputs are.