you insert data in anyway but working of Johnson's counter will not change right ?
It will be same as i have written in the answer.
So suppose instead of entering 1000 you entered 0001,
then it will start generating like 0001->0000 -> 1000.... and so on. i.e. 1->0->8
But i know that the output should be 1000-> 1100 -> 1110 .... i.e. 8 ->12 -> 14
So by looking at the pattern i would be sure that i have written entered data incorrectly.
We are just saying that leftmost is MSB and rightmost is LSB but who cares. You can treat the input and outputs whichever way you want. I can say that i will treat my MSB as righmost bit and leftmost bit as LSB and accordingly assume my inputs and outputs produced in decimal format. i.e. 0001 means 8 to me.