the IRS uses JCL for all it's production jobs, Java is no exception
        
        the IRS has a number of tools to change the JCL before each run
        substituting the current file names for the current run
        
        so... JCLPlay4 is the closest to production support we see
        
//USER900D JOB (),CLASS=A,MSGLEVEL=(1,1),MSGCLASS=D,NOTIFY=&SYSUID,
//   REGION=0M
//********************************************************************
//* Run Java under a UNIX System Service shell
//********************************************************************
//JAVA EXEC PGM=BPXBATSL,
// PARM='PGM /usr/lpp/java/J8.0/bin/java org.example.mainframe.play.samx
//             ple.JCLPlay4Appl'
//INFILE DD PATH='/u/jearl/data/population.csv',  <- this is an input file used by the Java code
// PATHOPTS=ORDONLY
//PROPS DD *                                      <- this is my "properties" for the current run
chunksize=100
years.to.process=1971,1972,1980,1990
/*
//DATA DD *                                       <- this is a second input file, inline within the JCL
China
Kyrgyz Republic
Philippines
Qatar
Sweden
Zimbabwe
/*
//FILEOUT DD DSNAME='USER900.POP.RESULTS',DISP=SHR  <- this is an output file used by the Java code
//STDIN  DD DUMMY
//STDOUT DD PATH='/u/user900/jclplay4.out',
// PATHOPTS=(OWRONLY,OCREAT,OTRUNC),
// PATHMODE=SIRWXU
//STDERR DD PATH='/u/user900/jclplay4.err',
// PATHOPTS=(OWRONLY,OCREAT,OTRUNC),
// PATHMODE=SIRWXU
//STDENV DD *
CLASSPATH=/u/user900/JCLPlay4.jar:/u/jearl/jars/*
JAVA_HOME=/usr/lpp/java/J8.0_64
PATH=/usr/lpp/java/J8.0_64/bin
/*
//
        
        
        this Java code reads a large population file, extract specific country data
        for specific years and create a report