vit has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks,
I am running my web app using Perl/CGI on Apache server (Not Tomcat) under Linux.
From there I call compiled Java codes as jar files, e.g. 
my @ar = `java -jar $path_to_jar/NounPhraseExtractionStandAlone.jar "$
+models_dir" "$text"`;

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which works pretty well on my localhost with Apache Tomcat. It also works well when I run it on the external server in a command line like 
# perl -e '{@ar = `java -jar $path_to_jar/NounPhraseExtractionStandAlo
+ne.jar "$models_dir" "$text"`; print "$a[0]\n"}'

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However inside the application it does not work. I checked $path_to_jar using some Perl code instead of Java placed at the same place as jar and it works fine.
Any help/advice is appreciated.

Replies are listed 'Best First'.
Re: Call jar from Perl/CGI on Apache Server with Linux
by blue_cowdawg (Monsignor) on Mar 18, 2013 at 14:11 UTC
        I am running my web app using Perl/CGI on Apache server (Not Tomcat) under Linux.

    Why are you not using a web container like Tomcat? Or JBoss? Or Geronimo?

    This is a rather bizarre implementation to say the least. Not one that I'd recommend in any form of production code. I just did a super search and came up empty, but somewhere in the Monastery catacombs exists a troubleshooting checklist for issues with CGI. Off the top of my head I'd suggest checking the following:

    • File permissions: quite frequently the CGI environment is running as a user other than what you are running as when executing from the command line.
    • Server Logs: Usually a font of information as to "why this ain't working."
    • Put debugging code into your CGI

    To that last point I always recommend you run the following code as a CGI (or some form of it) and quickly remove it from your production environment: 

    #!/usr/bin/perl -w 
use strict;
use CGI qw/ :all /;
use CGI::Carp qw/ fatalsToBrowser /;

print header,start_html;
print h1('Environmental Variables');
print ul(map{li($_ . ": " . $ENV{$_})} sort keys %ENV);
print h1('CGI Parameters');
print ul(map{li($_ . ": ". param($_))} sort param());
print end_html;
exit(0);

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    This code will give you some idea of what is going on in you CGI environment.

    Peter L. Berghold -- Unix Professional
    Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg
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[d/l]
Re: Call jar from Perl/CGI on Apache Server with Linux
by Anonymous Monk on Mar 18, 2013 at 14:48 UTC
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Re: Call jar from Perl/CGI on Apache Server with Linux
by RichardK (Parson) on Mar 18, 2013 at 14:18 UTC

    It might help to look at the status returned from your backticks by printing $?

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