How to handle file download popup

searchtextbox.sendkeys(Keys.chord(Keys.Control,Keys.SUB));

WebDriver driver=new FirefoxDriver();

driver.get("https://www.seleniumhq.org/download/");

Firefoxprofile profile=new Firefoxprofile();

String Key=browser.helperApps.neverAsk.SaveToDisk";

String value="application/zip";

profile.setpreference(key.value);

Webdriver driver=new FirefoxDriver(profile);

driver.findElement(By.xpath("//tbody/tr[1]/td[4]/a[1]")).click();