code: public static String toRawBinaryString(
      final char k)
    {
      final StringBuilder b = new StringBuilder(16);
      int z = (int) k;
      for (int i = 0; i < 16; ++i) {
        if ((z & 1) == 1) {
          b.insert(0, "1");
        } else {
          b.insert(0, "0");
        }
        z >>= 1;
      }
  
      return b.toString();
    }
docs: Show the given raw packed {@code binary16} value as a string of
  binary digits.
  
  @param k A packed {@code binary16} value
  
  @return A string representation