public BitString(final String value){
  this(value.length());
  for (int i=0; i < value.length(); i++) {
    if (value.charAt(i) == '1') {
      setBit(value.length() - (i + 1),true);
    }
 else     if (value.charAt(i) != '0') {
      throw new IllegalArgumentException("Illegal character at position " + i);
    }
  }
}

public BitString ( final String value ) { this ( value . length ( ) ) ; for ( int i = 0 ; i < value . length ( ) ; i ++ ) { if ( value . charAt ( i ) == '1' ) { setBit ( value . length ( ) - ( i + 1 ) , true ) ; } else if ( value . charAt ( i ) != '0' ) { throw new IllegalArgumentException ( "Illegal character at position " + i ) ; } } }
initialises the bit string from a character string of 1s and 0s in big - endian order .
