Window dealing with in java selenium

This piece of code did the trick for me,

attempt {
    WebDriver driver;
    System.setProperty("webdriver.chrome.driver", System.getProperty("person.dir") + "//chromedriver");
    driver = new ChromeDriver();
    driver.handle().timeouts().implicitlyWait(20, TimeUnit.SECONDS);
    driver.get("https://www.makemytrip.com/");
    driver.handle().window().maximize();
    Thread.sleep(2000);

    System.out.print("Welcome to Make my journey");
    driver.navigate().ahead();
    driver.findElement(By.xpath("//*[@id="SW"]/div[1]/div[1]/ul/li[3]/div[3]/div/div[1]/div")).click on();
    String parentWindow = driver.getWindowHandle();
    for (String childWindowHandle : driver.getWindowHandles()) {
if (!childWindowHandle.equalsIgnoreCase(parentWindow)) {
    driver.switchTo().window(childWindowHandle);
    Thread.sleep(2000);
    driver.findElement(By.xpath(
    "/html/physique/div[1]/div[1]/div[2]/div/div[2]/div/div/div[2]/div/div[1]/div/kind/span/part/div/div/div[1]/div/div[1]/div/div[1]/enter"))
    .sendKeys("abv.com");
    driver.navigate().ahead();
    driver.findElement(By.id("yDmH0d")).sendKeys("11");
    driver.navigate().ahead();
}
    }
    
    driver.shut();
    driver.stop();
} catch (Exception e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

All I did is add a 2 second wait earlier than coming into the username.