Problem2.java

public class Problem2 {
    public static void main(String... args) {
        List<Integer> data = new ArrayList<>();
        int ix = 0;
        while (true) {
            ix++;
            int v = fib(ix);
            if(v > 4_000_000) break;
            data.add(v);
        }
        int value = data.stream().filter(e -> e % 2 == 0).reduce(0, (x, y) -> x + y);
        System.out.println(value);
    }

    private static int fib(int x) {
        if(x <= 1) return 1;
        if(x == 2) return 2;
        return fib(x - 2) + fib(x - 1);
    }
}