List<WebElement> is not storing all the required elements in selenium

My myntra wishlist has 41 products, of which 19 are out of stock. I tried printing the names of the 'out of stock' products.

'out of stock' elements had a common class name using which I identified the product's name using xpath by traversing through parent and child nodes.

when i validated it in console, it gave the right response. It showed 19 products and when i hovered the mouse pointer it highlighted the out of stock products as expected. Works as expected when i debugged the code too.

But when i hit run, it printed only 7 products, size of the list was 7.

The page initially displays top 20 products and later displays the remaining as we scroll down. Out of the top 20, 7 are out of stock. Could this be a reason. If that is the case, how to handle this scroll event?

Here's the code snippet:

import java.util.List;
import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.openqa.selenium.support.ui.WebDriverWait;
public class stockout {
public static void main(String[] args) {
System.setProperty("webdriver.chrome.driver", "path of chromedriver.exe");	
WebDriver driver = new ChromeDriver();
WebDriverWait w =new WebDriverWait(driver,30);
driver.get(myntra login page);
//enter phone number	      driver.findElement(By.xpath(("//div[@class='signInContainer']/div[2]/div/input"))).sendKeys(phone number);
driver.findElement(By.cssSelector("div.submitBottomOption")).click();
Thread.sleep(2000);
driver.findElement(By.xpath("//div[@class='bottomeLink']/span")).click();
//enter password
driver.findElement(By.xpath("//input[@type='password']")).sendKeys(password);
driver.findElement(By.cssSelector("button.btn.primary.lg.block.submitButton")).click();
Thread.sleep(4000);
//open wishlist
driver.findElement(By.cssSelector("span.myntraweb-sprite.desktop-iconWishlist.sprites-headerWishlist")).click();
//add out of stock elements to a list
List<WebElement> outofstock = driver.findElements(By.xpath("//img[@class='itemcard-outOfStockItemImage itemcard-itemImage']/parent::picture/parent::a/parent::div/parent::div/div[2]/div/p[1]"));
//explicit wait
w.until(ExpectedConditions.visibilityOfAllElements(outofstock));
System.out.println(outofstock.size());
System.out.println("Items out of stock:");
for (WebElement product: outofstock)
{	System.out.println(product.getText());
}
}
}

Found the solution on the net, but wondering if there's any simpler way to do this. Suggestions are welcomed.

I added this piece of code to scroll down and it worked:

try {
Object lastHeight = ((JavascriptExecutor) driver).executeScript("return document.body.scrollHeight");
while (true) {
((JavascriptExecutor) driver).executeScript("window.scrollTo(0, document.body.scrollHeight);");
Thread.sleep(2000);
Object newHeight = ((JavascriptExecutor) driver).executeScript("return document.body.scrollHeight");
if (newHeight.equals(lastHeight)) {
break;
}
lastHeight = newHeight;
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}

You can use the following code if you are expecting a specific number of elements to be present.

new WebDriverWait(driver,10).until(ExpectedConditions.numberOfElementsToBe(By by, 19));