GnuCOBOL / Discussion / Help getting started: Calling GNUCobol from Java

Simon Sobisch - 2016-01-18

Just a note if you ever want to compile that much modules into a single dynamically linked library:
Compile each one with cobc -c (resulting in an assembled, but not linked file, in most cases prog.o) and link the final combined one with cobc -b *.o. This way you have to only recompile changed modules afterwards, not the complete application.

For the actual JAVA-part I'd do what Bill already suggested: have less as possible "external" entry points (you can code a caller which you pass the program to CALL along with the parameters) and leave all the other (existing) COBOL modules as a single file.

Simon

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Brian Tiffin - 2016-01-18

But, unless you tell me not to, Gary, I'd like to include that listing in the FAQ as Simon pointed out. Looks worthy of sharing.

Cheers,
Brian

Last edit: Brian Tiffin 2016-01-18

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- Gary Cowell - 2016-01-18
  
  Sure Brian, go ahead.
  
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  - Brian Tiffin - 2016-01-20
    
    In at, http://open-cobol.sourceforge.net/faq/index.html#can-gnucobol-interface-with-java
    
    If you notice anything you'd like fixed or improved, drop a note.
    
    Thanks, Gary.
    
    Cheers,
    Brian
    
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      Anonymous - 2016-01-20
      
      Looks okay to me
      
      Looks okay to me
      
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Oscar - 2016-01-18

creating one cobol stub program as an interface to your 3,500 cobol program which will call other modules based on fuction code that can help.

Last edit: Oscar 2016-01-18

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Gary Cowell - 2016-01-18

The COBOL programs come out of a program generator. So, the answer is "yes and no". I'll check out the linking options for the shared object, thanks.

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Anonymous - 2018-08-27

Hi All,

I am very new to COBOL and everything and was wondering if you can help me understand if I need any specific pre-requisites or COBOL related software to make Garry's program work on my Local?

I am good with JAVA but couldn't understand if anything else is required to execute .cbl file using above program as I get below exception:

subtest Exceptionjava.lang.UnsatisfiedLinkError: Unable to load library 'cobsubtest': The specified module could not be found.

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- Simon Sobisch - 2018-08-27
  
  As you need javac to comple .java to .class (and maybe creating a jar/exe whatever later) you'll need cobc to compile the execute.cbl to an object file or shared object or C library.
  
  Actually Gary had shown this as
  
  $ javac -classpath ./jna-4.2.1.jar jnacob.java $ cobc -o libcobsubtest.so cobsubtest.cbl $ cobc -o libcobsubtest2.so cobsubtest2.cbl $ java -classpath ./jna-4.2.1.jar:. jnacob
  
  For a summary of this thread see https://open-cobol.sourceforge.io/faq/index.html#java-native-access
  
  cobc is the GnuCOBOL compiler executable, so yes: you'll need to have GnuCOBOL installed to follow this examples.
  
  A summary about ways to do this can be found at https://open-cobol.sourceforge.io/faq/index.html#how-do-i-install-gnucobol - in case you have any issues give the search in the discussion boards a short try and post a new topic if you still have questions.
  
  Last edit: Simon Sobisch 2018-08-27
  
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I was trying to call cobol from java using JNA, i used the same example demostrated here but i am getting this error

Libcob Exceptionjava.lang.UnsatisfiedLinkError: Unable to load library 'cob': Native library (win32-x86-64/cob.dll) not found in resource path
([file:/C:/Users/XXXXX/eclipse-workspace/first%20project/, file:/C:/Users/XXXXX/eclipse-workspace/first%20project/jna-4.5.1.jar])

subtest Exceptionjava.lang.UnsatisfiedLinkError: Unable to load library 'cobsubtest': Native library (win32-x86-64/cobsubtest.dll) not found in resource path
([file:/C:/Users/XXXXX/eclipse-workspace/first%20project/, file:/C:/Users/XXXXX/eclipse-workspace/first%20project/jna-4.5.1.jar])

then i changed the library "cob" to "libcob-4" because there is no cob.dll nor libcob.dll.

After that i get below error now i don't know what is wrong please help.

"Libcob Exceptionjava.lang.UnsatisfiedLinkError: %1 is not a valid Win32 application."

Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

C:\Users\XXXXXXXX>cobc -i
cobc (GnuCOBOL) 3.1-dev.0
Copyright (C) 2019 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Written by Keisuke Nishida, Roger While, Ron Norman, Simon Sobisch, Edward Hart
Built     Sep 01 2019 23:33:31
Packaged  Aug 28 2019 17:45:18 UTC
C version (MinGW) "6.3.0"

build information
build environment        : i686-pc-mingw32
CC                       : gcc
C version                : (MinGW) "6.3.0"
CPPFLAGS                 : -I/mingw/include
CFLAGS                   : -O2 -pipe -finline-functions -fsigned-char
                           -Wall -Wwrite-strings -Wmissing-prototypes
                           -Wno-format-y2k -U_FORTIFY_SOURCE
LD                       : c:/gc30x-build/mingw/mingw32/bin/ld.exe
LDFLAGS                  :

GnuCOBOL information
COB_CC                   : gcc
COB_CFLAGS               : -I/mingw/include -Wno-unused -fsigned-char
                           -Wno-pointer-sign -I/mingw/include -pipe
COB_LDFLAGS              :
COB_LIBS                 : -L/mingw/lib -lcob
COB_CONFIG_DIR           : /mingw/share/gnucobol/config
  env: COB_CONFIG_DIR    : C:\GnuCOBOL\config
COB_COPY_DIR             : /mingw/share/gnucobol/copy
  env: COB_COPY_DIR      : C:\GnuCOBOL\copy
COB_MSG_FORMAT           : GCC
COB_OBJECT_EXT           : o
COB_MODULE_EXT           : dll
COB_EXE_EXT              : .exe
64bit-mode               : no
BINARY-C-LONG            : 4 bytes
endianness               : little-endian
native EBCDIC            : no
extended screen I/O      : pdcurses
variable file format     : 0
sequential file handler  : built-in
ISAM file handler        : VBISAM
mathematical library     : GMP
XML library              : disabled
JSON library             : disabled

Last edit: thomas 2019-09-04

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Simon Sobisch - 2019-09-04

I guess java --version shows "64-Bit Server VM" correct (the initial call to "cob" searched for a 64bit version of the dll)?
You can only call to JNA for system libraries that share the same architecture and your GnuCOBOL seems 32bit. So either use a 32bit version of java (you can setup multiple java environments in eclipse) or use a 64bit version of GnuCOBOL (and have the modules compiled as 64bit with the same compiler).

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thomas - 2019-09-05

Thanks Simon, i am now using 32 bit java and it is working as expected.

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Anonymous - 2021-07-12

Hi,
I am trying to run jnacob class , using the example but I am getting this error:

java -classpath ./jna-4.2.1.jar; jnacob

Libcob Exceptionjava.lang.UnsatisfiedLinkError: Unable to load library 'cob': Native library (win32-x86/cob.dll) not found in resource path ([file:/D:/Cobol/javacobol/jna-4.2.1.jar, file:/D:/Cobol/javacobol/])
subtest Exceptionjava.lang.UnsatisfiedLinkError: Unable to load library 'cobsubtest': Native library (win32-x86/cobsubtest.dll) not found in resource path ([file:/D:/Cobol/javacobol/jna-4.2.1.jar, file:/D:/Cobol/javacobol/])

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I did some changes, now I have this:

D:\Cobol\javacobol>java -cp jna-5.8.0.jar; jnacob
subtest Exceptionjava.lang.UnsatisfiedLinkError: Unable to load library 'cobsubtest':
The specified module could not be found.

The specified module could not be found.

Native library (win32-x86/cobsubtest.dll) not found in resource path ([file:/D:/Cobol/javacobol/jna-5.8.0.jar, file:/D:/Cobol/javacobol/])

I am using:
C:\Program Files (x86)\Java\jdk1.8.0_291\bin

cobc (GnuCOBOL) 3.2-dev.0
Copyright (C) 2021 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Written by Keisuke Nishida, Roger While, Ron Norman, Simon Sobisch, Edward Hart
Built     Jul 07 2021 21:51:20
Packaged  Jul 07 2021 11:11:20 UTC
C version (MinGW) "9.2.0"

build information
build environment        : i686-pc-mingw32
CC                       : gcc
C version                : (MinGW) "9.2.0"
CPPFLAGS                 :
CFLAGS                   : -O2 -pipe -finline-functions -fsigned-char
                           -Wall -Wwrite-strings -Wmissing-prototypes
                           -Wno-format-y2k
LD                       : c:/mingw/mingw32/bin/ld.exe
LDFLAGS                  :

GnuCOBOL information
COB_CC                   : gcc
COB_CFLAGS               : -pipe -I/usr/local/include -Wno-unused
                           -fsigned-char -Wno-pointer-sign
COB_DEBUG_FLAGS          : -ggdb3 -fasynchronous-unwind-tables
COB_LDFLAGS              :
COB_LIBS                 : -L/usr/local/lib -lcob -lm
COB_CONFIG_DIR           : C:/MinGW/msys/1.0/local/share/gnucobol/config
  env: COB_CONFIG_DIR    : D:\gnucobol\config
COB_COPY_DIR             : C:/MinGW/msys/1.0/local/share/gnucobol/copy
COB_MSG_FORMAT           : GCC
COB_OBJECT_EXT           : o
COB_MODULE_EXT           : dll
COB_EXE_EXT              : .exe
64bit-mode               : no
BINARY-C-LONG            : 4 bytes
endianness               : little-endian
native EBCDIC            : no
extended screen I/O      : pdcurses
variable file format     : 0
sequential file handler  : built-in
indexed file handler     : BDB
mathematical library     : GMP
XML library              : disabled
JSON library             : cjson

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Simon Sobisch - 2021-07-12

I'm not sure which jnacob you exactly use, in any case: for being able to load GnuCOBOL you have to have the setup as you have shown.

As you seem to want to run COBOL modules: test with cobcrun first (for example you likely have to adjustCOB_LIBRARY_PATH to include the place where the COBOL modules reside).

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Anonymous - 2021-07-15

I found out the problem, on windows you should run:
cobc -o libcobsubtest.dll cobsubtest.cbl

It worked!

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Calling GNUCobol from Java

A free COBOL compiler

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Calling GNUCobol from Java

Calling GNUCobol from Java

A free COBOL compiler

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