code: public static String unescape(String in) {
          StringBuilder out = new StringBuilder();
          char last = 0;
          for (char c : in.toCharArray()) {
              if (c == ESC) {
                  if (last != 0 && last == ESC)
                      out.append(c);
              } else
                  out.append(c);
              last = c;
          }
          return out.toString();
      }
docs: Unescaped a \ escaped string.
  
  @param in backslash escaped string
  @return unescaped string