#!/usr/bin/perl
use strict;

my %classes;

if(@ARGV == 0) {
  die "Please pass at least one jar file through the command line.\n";
}

foreach my $file (@ARGV) {
  print "Reading $file\n";
  open my $jar, "jar tf $file|" or die "Cannot open jar: $!\n";
  while(<$jar>) {
    chomp;
    next if (!/^.*\.class$/);
    push(@{$classes{$_}}, $file);
  }
}
foreach my $class (sort keys %classes) {
  if(@{$classes{$class}} > 1) {
    my $line = "$class =>";
    foreach my $file (@{$classes{$class}}) {
      $line .= " $file";
    }
    print "$line\n";
  }
}