@Test
public void testSimpleTimer() {
    long startTime = System.currentTimeMillis();
    int data = 0;
    for(int i = 0; i < 1_000_000; i++) {
        data += 1;
    }
    long elapsedTime = System.currentTimeMillis() - startTime;
    System.out.println(elapsedTime);
}

public class StopWatchTest {

    private StopWatch stopWatch;

    @Before
    public void setUp() {
        stopWatch = new StopWatch("honeymon");
    }

    /**
     * Long 타입과 BigDecimal 타입의 덧셈 소요시간 비교:
     */
    @Test
    public void testAddLongAndBigDecimal() {
        BigDecimal bigDecimal = BigDecimal.valueOf(0, 0);
        Long longType = 0L;

        stopWatch.start("Long type");
        for(int i = 0; i < 1_000_000; i++) {
            longType += 1L;
        }
        stopWatch.stop();

        stopWatch.start("BigDecimal type");
        for(int i = 0; i < 1_000_000; i++) {
            bigDecimal = bigDecimal.add(BigDecimal.ONE);
        }
        stopWatch.stop();
        System.out.println(stopWatch.shortSummary());
        System.out.println(stopWatch.getTotalTimeMillis());
        System.out.println(stopWatch.prettyPrint());
    }
}