I'm not sure why everyone keeps using string eval to load modules. Heck, even UNIVERSAL::require does it, which confounds the heck out of me.

sub my_require
{
  my $class = shift;
  (my $pm = $class) =~ s(::)(/);
  $pm .= '.pm';

  require $pm;
  # optional:
  # $class->import();
}
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Then it's as simple as eval { my_require($handlerClass); }. Eliminating all the delays and risks of string eval. Of course, if someone can put a new module in your @INC and update your table, that someone could be malicious, but I don't think there's much that you can do about that.