question: 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 ) ; } } }
target:  Initialises the bit string from a character string of 1s and 0s in big-endian order.