Hi monks,
Thanks all for your help.
Now things become clear to me. One doubt. What role does Class::MethodMaker play here?
I use Class::MethodMaker as follows in both A.pm and B.pm

use Class::MethodMaker
  'new_with_init' => "new" ,
  'new_hash_init' => "_hash_init" ,
  'get_set'       => [ qw(method1 ) ];
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Because when I use my own new method without Class::MethodMaker,though I get subroutine redefined warnings, I get 'Perl Sybtax ok' message.
But with Class::MethodMaker compilation gets aborted.

Thank you!!