Scroll UP or Down a page in Selenium Webdriver

gistfile1.txt

https://www.guru99.com/scroll-up-down-selenium-webdriver.html#2
https://stackoverflow.com/questions/12293158/page-scroll-up-or-down-in-selenium-webdriver-selenium-2-using-java

For Scroll down:
WebDriver driver = new FirefoxDriver();
JavascriptExecutor jse = (JavascriptExecutor)driver;
jse.executeScript("window.scrollBy(0,250)", "");

OR, you can do as follows:
jse.executeScript("scroll(0, 250);");

For Scroll up:
jse.executeScript("window.scrollBy(0,-250)", "");
OR,
jse.executeScript("scroll(0, -250);");