docs: public static String unescapeJava(String str) {
          if (str == null) {
              return null;
          }
          try {
              StringWriter writer = new StringWriter(str.length());
              unescapeJava(writer, str);
              return writer.toString();
          } catch (IOException ioe) {
              // this should never ever happen while writing to a StringWriter
              ioe.printStackTrace();
              return null;
          }
      }