Java Batch

I've spent much of this morning looking for some comparison between
the performance of Java and COBOL for batch programming on z/OS.  I
haven't found any useful information and am hoping I might find some
here.

I know that IBM bought the JZOS product a couple years back with the
intent of enabling Java in the batch world.
Has this taken off?

Also read somewhere that given that Java has to be reinterpreted (from
the bytecode produced by compilation) by the JVM at runtime, there is
no way it could outperform COBOL in classical batch processes like
payroll or month-end credit card statement processing.

Is this so?

Would really appreciate hearing from anyone who has experience with
JZOS or other forms of running batch Java on MVS.

Thanks!