private void validateInput(String n1, String n2) {
        if (n1 == null || n2 == null) {
            throw new IllegalArgumentException("n1 and n2 parameters can't be null");
        }
    }
This solution is the faster I've found. It's similar to how a human sum two binary numbers.

The complexity order of this algorithm is O(N) where N is the number of digits of the biggest
binary number. This is the faster implementation because we are not parsing data from binary
to integer and then from integer to binary.

To solve this problem is needed go through the String from right to left, and take always
into account the accumulated value of the sum and carry.
src/main/java/com/github/pedrovgs/problem3/SumBinaryNumbers.java