Building programs: compile and link JCL examples

For complete documentation about building COBOL applications, including Object Oriented (OO) COBOL, see Enterprise COBOL for z/OS, V4R2, Programming Guide.

For compiling with JCL, IBM® provides a set of cataloged procedures to reduce the amount of JCL coding that you need to write. If the cataloged procedures do not meet your needs, you can write your own JCL. Using JCL, you can compile a single program or compile several programs as part of a batch job. See Invoking z/OS Batch Runtime for more information.

The compiler translates your COBOL program into language that the computer can process (object code). The compiler also lists errors in your source statements and provides supplementary information to help you debug and tune your program. Use compiler-directing statements and compiler options to control your compilation. After compiling your program, you need to review the results of the compilation and correct any compiler-detected errors.

To build Java™ programs, use the javac command to create the classes and the jar command for packaging. This documentation focuses on building a typical use case that updates a traditional COBOL program to call out to Java methods in which either or both can use DB2®.

The JCL example shown in Figure 1 is a modification of a sample COBOL DB2 phone program that ships as part of IBM DB2 for z/OS®. This program is typically found in hlq.sdsnsamp(DSN8BC3) and is often used in the DB2 installation verification program (IVP). The COBOL source is modified to invoke a simple Java "Hello World" method that also selects rows from the DB2 catalog using the SYSIBM schema. The following are implications on the DB2 provided COBOL build procedure to run in the z/OS Batch Runtime container:

The Language Environment® Runtime library CEE.SCEERUN must be in the JOBLIB for the Java JNI support.
The ATTACH(RRSAF) must be in the preprocessor portion of the catalogued procedure. Although optional, this forces the generation of RRS attach entry point at compile time. Omit this option for attach-neutral code generation. The z/OS Batch Runtime requires the use of RRS attach to be bound at compile (as in this example), link (include DSNRLI), or runtime (include DSNULI).
The use of Java from COBOL source requires the compile options RENT,DLL,THREAD.
The long names required for the Java JNI imply use of PDSE libraries by the binder (rather than traditional PDS load libraries).
The input to the Binder requires both the Enterprise COBOL Java linkage and JNI export (*.x) files.

Figure 1. Example: JCL for COBOL DB2 phone program

//COBBUILD   JOB (MOP,1458),'STEVE',CLASS=A,REGION=0M,                          
//     MSGLEVEL=(1,1),MSGCLASS=X,TIME=1440,NOTIFY=&SYSUID                     
//*                                                                             
//**********************************************************************        
//*  NAME = DSNTEJ2C -- MODIFIED FOR RRS AND Java BATCH CONTAINER RUN  *        
//*                     BUILD ONLY WITH APP CALL TO JAVA               *        
//*  DESCRIPTIVE NAME = DB2 SAMPLE APPLICATION W CALL TO JAVA          *        
//*                     PHASE 2                                        *        
//*                     COBOL                                          *        
//*                                                                    *        
//*    LICENSED MATERIALS - PROPERTY OF IBM                            *        
//*    5635-DB2                                                        *        
//*    (C) COPYRIGHT 1982, 2006 IBM CORP.        *        
//*                                                                    *        
//*    STATUS = VERSION 9                                              *        
//*                                                                    *        
//*  FUNCTION = THIS JCL PERFORMS THE PHASE 2 COBOL SETUP FOR THE      *        
//*             SAMPLE APPLICATIONS.  IT PREPARES AND EXECUTES         *        
//*             COBOL BATCH PROGRAMS.                                  *  
//*                                                                    *  
//*             THIS JOB IS RUN AFTER PHASE 1.                         *  
//*                                                                    *  
//*                                                                    *  
//* CHANGE ACTIVITY =                                                  *  
//*                                                                    *  
//**********************************************************************  
//JOBLIB  DD  DISP=SHR,DSN=DSN910.NEWFUNC.SDSNEXIT                        
//        DD  DISP=SHR,DSN=DSN910.SDSNLOAD                                
//        DD  DISP=SHR,DSN=CEE.SCEERUN                                    
//*                                                                       
//*        PREPARE COBOL PHONE PROGRAM                                    
//PH02CS03 EXEC DSNHNCOB,MEM=XMPCOBJV,                                    
//         COND=(4,LT),                                                   
//         PARM.PC=('HOST(IBMCOB)',APOST,APOSTSQL,SOURCE,                 
//         NOXREF,'SQL(DB2)','DEC(31)','ATTACH(RRSAF)'),                  
//         PARM.COB=(NOSEQUENCE,LIB,QUOTE,RENT,'PGMNAME(LONGUPPER)',      
//         DLL,THREAD)                                                    
//PC.DBRMLIB   DD DSN=DSN910.DBRMLIB.DATA(XMPCOBJV),                     
//             DISP=SHR                                                  
//PC.SYSLIB    DD DSN=SUIMGJB.PRIVATE.DSN910.SRCLIB.DATA,                
//             DISP=SHR                                                  
//PC.SYSIN     DD DSN=SUIMGJB.PRIVATE.JCL.CNTL(XMPCOBJV),                
//             DISP=SHR                                                  
//COB.SYSLIB   DD DSN=SUIMGJB.PRIVATE.JNI.COPY,                          
//             DISP=SHR                                                  
//LKED.SYSLMOD DD DSN=SUIMGJB.PRIVATE.LIBRARY(XMPCOBJV),                 
//             DISP=SHR                                                  
//LKED.RUNLIB  DD DSN=DSN910.RUNLIB.LOAD,                                
//             DISP=SHR                                                  
//LKED.SYSIN   DD *                                                      
     INCLUDE SYSLIB(DSNRLI)                                              
     INCLUDE RUNLIB(DSN8MCG)                                             
     INCLUDE '/home/cob42/cobol/lib/igzcjava.x'                          
     INCLUDE '/usr/lpp/java/J6.0/lib/s390/j9vm/libjvm.x'                 
//