One loop outperforms two

Main.java

public class Main {
    private static final int SIZE = 5_000_000;
    private static final int[] arr1 = initArray(SIZE);
    private static final int[] arr2 = initArray(SIZE);

    public static void main(String[] args) throws InterruptedException {
        // warmup
        long[] results = new long[6];
        results[0] = twoLoops();
        results[1] = oneLoop();

        results[2] = twoLoops();
        results[3] = oneLoop();

        // give the jit time to recover
        Thread.sleep(1000);

        long time1 = System.currentTimeMillis();
        results[4] = oneLoop();
        long endTime1 = System.currentTimeMillis();
        long time2 = System.currentTimeMillis();
        results[5] = twoLoops();
        long endTime2 = System.currentTimeMillis();
        System.out.println("Junk against optimization out: " + Arrays.toString(results));
        System.out.println("One Loop: " + (endTime1 - time1));
        System.out.println("Two Loops: " + (endTime2 - time2));
    }

    private static int[] initArray(int size) {
        Random random = new Random();
        int[] primitives = new int[size];
        for (int iter = 0 ; iter < primitives.length ; iter++) {
            primitives[iter] = random.nextInt();
        }
        return primitives;
    }

    private static long twoLoops() {
        long sum1 = 0;
        long sum2 = 0;
        for(int iter = 0 ; iter < arr1.length ; iter++) {
            sum1 += arr1[iter];
        }
        for(int iter = 0 ; iter < arr2.length ; iter++) {
            sum2 += arr2[iter];
        }
        return Math.max(sum1, sum2);
    }

    private static long oneLoop() {
        long sum1 = 0;
        long sum2 = 0;
        for(int iter = 0 ; iter < arr1.length ; iter++) {
            sum1 += arr1[iter];
            sum2 += arr2[iter];
        }
        return Math.max(sum1, sum2);
    }
}