gistfile1.builder

class Greeting
  def hello; end

  private do
    def bonjour; end
  end

  protected do
    def guten_morgen; end
  end
end

klass = Class.new

Greeting.public_instance_methods - klass.public_instance_methods # => ["hello"]
Greeting.private_instance_methods - klass.private_instance_methods # => ["bonjour"]
Greeting.protected_instance_methods - klass.protected_instance_methods # => ["guten_morgen"]