That example in article is straight up terrible. The Java version would be:

  var input = "Some kind of string.";  
  var output = Optional.of(input)
    .map(i -> i.trim())
    .map(i -> i.replace(' ', '-'))
    .map(i -> i.replaceAll("[./…]", ""))
    .map(i -> i.toLowerCase())
    .get();

That is until you realize there is no reason to go weird with arrow operators when String is an object:

  var input = "Some kind of string.";        
  var output = input.trim()
    .replace(' ', '-')
    .replaceAll("[./…]", "")
    .toLowerCase();

It looks like they solved the wrong issue but that is probably just side effect of using trivial examples.