locating GUI element in selenium webdriver

Locating elements in WebDriver is done by using the "findElement(By.locator())" method. The "locator" part of the code is same as any of the locators previously discussed in the Selenium IDE chapters of these tutorials. Infact, it is recommended that you locate GUI elements using IDE and once successfully identified export the code to webdriver. 
Here is a sample code that locates an element by its id. Facebook is used as the Base URL. 
<pre><code>
package newproject;
import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.firefox.FirefoxDriver;

public class PG2 {
    public static void main(String[] args) {
        System.setProperty("webdriver.gecko.driver", "C:\\geckodriver.exe");
        WebDriver driver = new FirefoxDriver();
        String baseUrl = "http://www.facebook.com";
        String tagName = "";

        driver.get(baseUrl);
        tagName = driver.findElement(By.id("email")).getTagName();
        System.out.println(tagName);
        driver.close();
        System.exit(0);
    }
}
</code></pre>
Summary for locating elements 
Variation |Description |Sample
-----|-----|-----
By.className |finds elements based on the value of the "class" attribute |findElement(By.className("someClassName"))
By.cssSelector |finds elements based on the driver's underlying CSS Selector engine |findElement(By.cssSelector("input#email"))
By.id |locates elements by the value of their "id" attribute |findElement(By.id("someId"))  
By.linkText |finds a link element by the exact text it displays |findElement(By.linkText("REGISTRATION"))  
By.name |locates elements by the value of the "name" attribute |findElement(By.name("someName"))  
By.partialLinkText |locates elements that contain the given link text |findElement(By.partialLinkText("REG"))  
By.tagName |locates elements by their tag name |findElement(By.tagName("div"))  
By.xpath |locates elements via XPath |findElement(By.xpath("//html/body/div/table/tbody/tr/td[2]/table/ tbody/tr[4]/td/table/tbody/tr/td[2]/table/tbody/tr[2]/td[3]/ form/table/tbody/tr[5]"))
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