Note- Use javascript because if any textbox is disabled then in that case sendKeys() method will not work.
ex- <input id=”txt2 class=”posStat type=”text disabled=”disabled maxlength=”100>

Reference Code-

import java.util.concurrent.TimeUnit;
import org.openqa.selenium.By;
import org.openqa.selenium.JavascriptExecutor;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.firefox.FirefoxDriver;

public class Naukari{
public static void main(String[] args)
{
             WebDriver driver = new FirefoxDriver();
            driver.manage().timeouts().implicitlyWait(10,TimeUnit.SECONDS);
            driver.get(“http://www.naukri.com”);
            driver.findElement(By.partialLinkText(“Post Resume”)).click(); //click in post resume
             WebElement user= driver.findElement(By.xpath(“//input[@id=’txt2′]”)); 

             //Enter your Email ID* : , textbox

            System.out.println(user.isEnabled()); //this will give false
            //user.sendKeys(“hello1”); //if u will try this, this will fail                                                                                                                                                                                                             ((JavascriptExecutor)driver).executeScript(“document.getElementById(‘txt2’).value=’ajay'”); //this is how , to use javascript to send value

            WebElement pass = driver.findElement(By.xpath(“//input[@id=’password’]”));                              //this field is not disabled so for this sendKeys() method can be used.

             System.out.println(pass.isEnabled()); //this will print true
             pass.sendKeys(“hello”); //this will send the value in, Create a Password for your                       account* :
      }
}

 

Source: http://selenium-makeiteasy.blogspot.com