Apart from that your sub make_closures doesn't return the array of closures so the code as supplied doesn't do anything , you have to realise that the reference to $j inside each of you generated closures is a reference to the $j in the sub make_closures(). Ie. They all refer to the same variable.

Here's a simple mod of your code that demonstrates the behavious that you were looking for... Maybe it will help clarify things.

#! perl -sw
use strict;

sub make_closures {
  my $j = 0;
  my @closures;

  while (++$j < 7) {
    my $jj = $j;
    push (@closures, sub {print $jj, "\n";});
  }
  return @closures;
}

foreach my $sub (&make_closures) {
  $sub->();
}

__DATA__
C:\test>205818
1
2
3
4
5
6
[download]

Here, I am creating a new var $jj inside the loop each time around and giving it the value, therefore each generated sub has its own independant variable/value, and the $j var gets garbage collected when it goes out of scope when make_closures() terminates.