code: public static char normalize(char ch){
          //this is even cheaper than the hashmap lookup. because it covers most use cases, it's worth the check.
          if (ch <= 127) { //ascii (basic latin)
              if (ch < 'A' || (ch < 'a' && ch > 'Z') || ch > 'z') {
                  return ' ';
              } else {
                  return ch;
              }
          }
  
          Character result = NORMALIZE_MAP.get(ch);
          return result == null ? ch : result;
      }
docs: Character Normalization (and exclusion).
  @return Normalized character, the space to exclude the character.