Data retrieval from Perl to Java - perl

Question

Currently, I am reading some data from Perl, I want to retrieve messages from Perl for each and every step. I tried using this code,
Process process = Runtime.getRuntime().exec(new String[] {"perl","C:\\Perl\\bin\\try.pl", "uname=test"});
BufferedReader reader =new BufferedReader(new InputStreamReader(process.getInputStream()));
String s = reader.readLine();
System.out.println("perl said [ " + s + " ]");
My perl script as follows,
$path_to_file = $ARGV[0] or die("argument not passed") ;
print "success";
# some code
If I dont receive any argument, then we need to retrieve the message, that there is no argument passed. like that I want log all the information. I tried giving print data. That is working. But if the argument is not passed. I want the data that argument not passed.
is it possible to retrieve?

Answer 1

I hereby found the answer for my above question,
Process process = Runtime.getRuntime().exec(new String[] {"perl","C:\\Perl\\bin\\try.pl", "uname=test"});
BufferedReader readError = new BufferedReader( new InputStreamReader(process.getErrorStream()));
s = readError.readLine();
System.err.println("perl said [ " + s + " ]");
By this way i capture the error details. Thanks for all your suggestions. Also, i changed my perl script as follows,
my $path_to_file = $ARGV[0] or {print " Argument not passed! " };