question: public void testPosNegFirstLonger ( ) { String numA = "2837462783428374767845648748973847593874837948575684767" ; String numB = "-293478573489347658763745839457637" ; String res = "-2837462783428374767845615168483972194300564226167553532" ; BigInteger aNumber = new BigInteger ( numA ) ; BigInteger bNumber = new BigInteger ( numB ) ; BigInteger result = aNumber . xor ( bNumber ) ; assertTrue ( res . equals ( result . toString ( ) ) ) ; }
target:  Xor for a positive and a negative numbers; the first is longer