Each FluentWait instance defines the maximum amount of time to wait for a condition, as well as the frequency with which to check the condition. Furthermore, the user may configure the wait to ignore specific types of exceptions whilst waiting, such as NoSuchElementExceptions when searching for an element on the page.It is associated with the driver.
Wait<WebDriver> wait = new FluentWait<WebDriver>(driver)
.withTimeout(30, SECONDS) //actuall wait for the element to pe present
.pollingEvery(5, SECONDS) //selenium will keep looking for the element after every 5seconds
.ignoring(NoSuchElementException.class); //while ignoring this condition
wait.until(ExpectedConditions.visibilityOf(driver.findElement(By.id("username"));