public static void main(String[] args) throws InterruptedException {
        java.util.Random random = new java.util.Random();
        long totalTimeSec = 0;
        long totalTimeMs = 0;
        int totalCount = 10;
        for (int i = 0; i < totalCount; i++) {
            Thread.sleep(random.nextInt(1000));

            long beginTimeMs = System.currentTimeMillis();
            long beginTimeSec = System.currentTimeMillis() / 1000;
            foo();
            long endTimeMs = System.currentTimeMillis();
            long endTimeSec = System.currentTimeMillis() / 1000;

            System.out.println(String.format("Pass %d: %d ms, %d sec", i, endTimeMs - beginTimeMs, endTimeSec - beginTimeSec));
            totalTimeMs += endTimeMs - beginTimeMs;
            totalTimeSec += endTimeSec - beginTimeSec;
        }
        System.out.println(String.format("Avg time: %f ms, %f sec", totalTimeMs / (double) totalCount, totalTimeSec / (double) totalCount));
    }

Pass 0: 170 ms, 0 sec
Pass 1: 170 ms, 0 sec
Pass 2: 171 ms, 1 sec
Pass 3: 170 ms, 0 sec
Pass 4: 170 ms, 0 sec
Pass 5: 170 ms, 0 sec
Pass 6: 170 ms, 0 sec
Pass 7: 170 ms, 1 sec
Pass 8: 170 ms, 0 sec
Pass 9: 170 ms, 0 sec
Avg time: 170,100000 ms, 0,200000 sec