code: public static String toBinaryString(final byte[] data) {
          if (data == null) {
              return null;
          }
          final StringBuilder buf = new StringBuilder(data.length * 8);
          for (final byte element : data) {
              byte bits = element;
              for (int j = 0; j < 8; j++) {
                  if ((bits & 0x80) == 0x80) {
                      buf.append('1');
                  } else {
                      buf.append('0');
                  }
                  bits <<= 1;
              }
          }
          return buf.toString();
      }
docs: Returns a string formatted by bits.
  
  @param data
  @return