WebDriver driver = new FirefoxDriver();
        driver.get("http://www.google.pl/");
        driver.manage().timeouts().implicitlyWait(5, TimeUnit.SECONDS);
        WebElement element = driver.findElement(By.name("q"));
        driver.manage().timeouts().implicitlyWait(5, TimeUnit.SECONDS);
WebElement query = driver.findElement(By.xpath("//html/body/div[2]/span/center/form/table/tbody/tr/td[2]/div/div/input"));

query.sendKeys("asd");

<input type="text" value="" autocomplete="off" name="q" class="gbqfif" id="gbqfq" style="border: medium none; padding: 0pt; margin: 0pt; height: auto; width: 100%; background: url("data:image/gif;base64,R0lGODlhAQABAID/AMDAwAAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw%3D%3D") repeat scroll 0% 0% transparent; position: absolute; z-index: 6; left: 0px; outline: medium none;" dir="ltr" spellcheck="false">

driver.findElement(By.id("gbqfq")).sendKeys("some text");

driver.findElement(By.xpath("//input[@id='gbqfq']")).sendKeys("some text");

driver.manage().timeouts().implicitlyWait(20, TimeUnit.SECONDS);

WebDriverWait wait = new WebDriverWait(driver, 20);
wait.until(ExpectedConditions.visibilityOfElementLocated(By.xpath("//html/body/div[2]/span/center/form/table/tbody/tr/td[2]/div/div/input")));

//input[@title='Google Search']

//input[@title='Szukaj w Google']

//html/body/center/form/table/tbody/tr/td[2]/div/input

//input[@title='Google Search']

WebDriver driver = new FirefoxDriver();
String baseUrl = "http://www.google.com";
Selenium selenium = new WebDriverBackedSelenium(driver, baseUrl);
selenium.open("http://www.google.com");
selenium.isElementPresent(XPath Variable);

driver.findElement(By.id("gbqfq")).sendKeys("xyz");