The problem is when those getters and setters have other effects (maybe invalidating a cache?). In Java, it's considered best to just go ahead and add the getters and setters first, so that when you need to add these side effects later you don't have to modify lots of code using your library (if that is even possible). Languages like Python make this unnecessary since they have first class properties:

  # Old
  class Foo(object):
      def __init__(self):
          self.x = 0
  foo = Foo()
  foo.x = 1

  # New
  class Foo(object):
      def __init__(self):
          self.__x = 0
      @property
      def x(self):
          return self.__x
      @x.setter
      def x(self, val):
          self.__x = val
          do_other_stuff()