recursive method in Java

[logistic_guy]

Write a recursive method that returns the number of \(\displaystyle 1\)’s in the binary representation of \(\displaystyle N\). Use the fact that this is equal to the number of \(\displaystyle 1\)’s in the representation of \(\displaystyle N/2\), plus \(\displaystyle 1\), if \(\displaystyle N\) is odd.