Using ProcessBuilder

Question

Hi All,
I am using ProcessBuilder in my java code to execute a perl script. The perl script sets up a server using the following code:
$server = IO::Socket::INET->new( Proto => 'tcp',
LocalPort => $PORT,
Listen => SOMAXCONN,
Reuse => 1);
die "Can't setup server\n" unless $server;
I get "Cannot setup server" message error message. The perl script runs fine and sets up a server successfully when run from the terminal. However when ProcessBuilder runs this script I get "Cannot setup server" error message. Before running the java code, I assured that the port the perl script uses is not in use.
Is it that I cannot do this with ProcessBuilder?
Can anyone please suggest a remedy/alternative to do this
Thanks,
Akhil

Answer 1

I am posting my reply again in a more readable form.
Here, is my simple Java code that forks a perl script named charniak-parser.pl
public class MyClass {
         public static String runProcess(List<String> command, java.util.Map<String, String> env) throws Exception {
                        ProcessBuilder pb = new ProcessBuilder(command);
                        pb.redirectErrorStream(true);
                        if(env.size() != 0){
                                 java.util.Map<String, String> environment = pb.environment();
                                 environment.putAll(env);
                        Process p = pb.start();
                        BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
                        StringBuilder sb= new StringBuilder();
                        String line;
                        while((line = br.readLine())!=null){
                                 sb.append(line '\n');
                        p.waitFor();
                        return sb.toString();
           public static void main(String[] args){
                       java.util.HashMap<String, String> env = new java.util.HashMap<String, String>();
                       env.put("CHARNIAK", "project/akhil/srl/CharniakServer/parser05May26fixed");
                       String message = runProcess(Arrays.asList("nohup", "/project/akhil/srl/CharniakServer/charniak-server.pl", "&>", "charniak-server.log", "&"), env);
                       System.out.println("message: " message);
}In the above code, I have set up an environment variable that is required by the perl script in it's execution.
Here, is the beginning code of my perl script (charniak-parser.pl):
#!/usr/bin/perl
$MAXCHAR = 799;
$MAXWORD = 400;
$charniakDir = "$ENV{CHARNIAK}";
$command = "$charniakDir/PARSE/parseIt $charniakDir/DATA/EN/ -K -l$MAXWORD";
#$endProtocol = "\n\n\n";
$endProtocol = "\n";
$TIMEOUT = 60; # undef if no timeout
$PORT = 4449; # pick something not in use
#read port
$PORT = $ARGV[0] if (scalar(@ARGV) > 0);
use Expect;
#create main program that will be communicating throught pipe.
$main = NewExpect($command);
sub NewExpect {
    my $command = shift;
    my $main;
    print "[Initializing...]\n";
    $main = new Expect();
    $main->raw_pty(1); # no local echo
    $main->log_stdout(0); # no echo
    $main->spawn($command) or die "Cannot start: $command\n";
    $main->send("<s> This is a test . </s>\n"); #send input to main program
   @res = $main->expect(undef,$endProtocol); # read output from main program
    print "[Done initializing.]\n";
    return $main;
#server initialization matter
use IO::Socket;
use Net::hostent; # for OO version of gethostbyaddr
$server = IO::Socket::INET->new( Proto => 'tcp',
                                                    LocalPort => $PORT,
                                                    Listen => SOMAXCONN,
                                                    Reuse => 1);
die "Can't setup server: $! " unless $server;
#end server initializationThe output of the java program is :
[Initializing...]
[Done initializing.]
Can't setup server:Before running the code, I always assure that the port 4449 is free.
If more information required, please let me know.
Akhil