code: static public String blockContents(byte[] value) {
          if (null == value) {
              return null;
          }
          char[] data = new char[value.length];
          for (int i = 0; i < data.length; i++) {
              data[i] = '*';
          }
          return new String(data);
      }
docs: Create a string that is the same length as the input, but filled with
  characters.
  
  @param value
  @return String