Sequential units - why does one of the solutions not work?

Question

Java

There is a simple task on Yandex.Interview "B. Consecutive Units".
Link https://contest.yandex.ru/contest/8458/problems/B/

made two solutions on Java 8
The first one passes all tests on Yandex successfully.

public class Application
{
    public static void main(String[] args) throws Exception {
        BufferedReader r = new BufferedReader(new FileReader("input.txt"));

        int size = Integer.valueOf(r.readLine());
        int[] sequence = new int[size + 1];
        for (int i = 1; i <= size; i++) {
            sequence[i] = Integer.valueOf(r.readLine());
        }

        System.out.println(longestSequence(sequence));
    }

    public static int longestSequence(int[] vector)
    {
        int maxLength = 0;
        int currentLength = 0;

        for (int i = 0; i <= vector.length - 1; i++)
        {
            if (vector[i] == 1)
            {
                currentLength++;
                maxLength = (currentLength > maxLength) ? currentLength : maxLength;
            }
            else
            {

                currentLength = 0;
            }
        }

        return maxLength;
    }
}

the second solution is shorter.
But only the first few tests are successful. Wrong answer verdict.

public class Application
{
   public static void main(String[] args) throws Exception {
        BufferedReader r = new BufferedReader(new FileReader("input.txt"));

        int maxLength = 0;
        int currentLength = 0;
        int value;
        String line;

        while ((line = r.readLine()) != null)
        {
            try {
                value = Integer.valueOf(line);
                if (value == 1) {
                    currentLength++;
                    maxLength = (currentLength > maxLength) ? currentLength : maxLength;
                } else {
                    currentLength = 0;
                }
            }
            catch (Exception e)
            {

            }
        }

        System.out.println(maxLength);
    }
}

According to my tests, everything is OK in both solutions.

Yes, in the second solution, I omitted the use of the first number n (number of vector elements).
In what situation does this begin to affect the result? Tell me plz