title: java.lang.IllegalArgumentException: Keys to send should be a not null CharSequence
body: <p>Getting this  Error : <code>java.lang.IllegalArgumentException: Keys to send should be a not null CharSequence.</code> How to resolve this issue?</p>
  
  <p>POM design model used using TestNG Framework</p>
  
  <p>Please find out the below code snippets for both the java classes I have added </p>
  
  <p>The below code snippet is LoginPageTest Java Class</p>
  
  <pre><code>package com.crm.qa.testcases; 
  
  import org.testng.Assert;
  import org.testng.annotations.AfterMethod;
  import org.testng.annotations.BeforeMethod;
  import org.testng.annotations.Test;
  
  import com.crm.qa.base.TestBase;
  import com.crm.qa.pages.HomePage;
  import com.crm.qa.pages.LoginPage;
  
  public class LoginPageTest extends TestBase{
  
      LoginPage loginpage;
      HomePage homepage;
  
      public LoginPageTest() {
          super();
      }
  
      @BeforeMethod
      public void setup() {
          initialization();
          loginpage = new LoginPage();
      }
  
       @Test(priority=1)
       public void loginpagetitletest() {
       String title = loginpage.ValidatePageTitle();
      Assert.assertEquals(title, "Login");
      } 
  
      @Test(priority=2)
      public void loginTest()
      {
          homepage = loginpage.login(prop.getProperty("emailId"),prop.getProperty("password"));
      }
  
      @AfterMethod
      public void Teardown() {
          driver.quit();
      }
  
  }
  </code></pre>
  
  <p>And the below snippet is LoginPage Java Class</p>
  
  <pre><code>package com.crm.qa.pages;
  
  import org.openqa.selenium.By;
  import org.openqa.selenium.WebElement;
  import org.openqa.selenium.interactions.Actions;
  import org.openqa.selenium.support.FindBy;
  import org.openqa.selenium.support.PageFactory;
  
  import com.crm.qa.base.TestBase;
  
  public class LoginPage extends TestBase {
  
      //Page Factory - object repository:
  
          @FindBy(id = "li_myaccount")
          WebElement myaccountbtn;
  
          //*[@id="li_myaccount"]/ul/li[1]/a
  
          @FindBy(xpath = "//a[contains(text(), 'login')]")
          WebElement loginbtn;
  
          @FindBy(name = "username")
          WebElement username;
  
          @FindBy(name = "password")
          WebElement password;
  
          @FindBy(xpath = "//*[@id='loginfrm']/button")
          WebElement lgnbtn;
  
          @FindBy(xpath = "//a[contains(text(), 'Sign Up')]")
          WebElement Signupbtn;
  
          //Initialize the Page Objects
      public LoginPage() {
          PageFactory.initElements(driver, this);
      }
  
      //Actions
      public String ValidatePageTitle() {
          return driver.getTitle();
      }
  
  
      public HomePage login(String un, String pwd) {
  
          username.sendKeys(un);
          password.sendKeys(pwd);
          myaccountbtn.click();
          loginbtn.click();
  
          return new HomePage();
          }
  
      } package com.crm.qa.pages;
  
  import org.openqa.selenium.By;
  import org.openqa.selenium.WebElement;
  import org.openqa.selenium.interactions.Actions;
  import org.openqa.selenium.support.FindBy;
  import org.openqa.selenium.support.PageFactory;
  
  import com.crm.qa.base.TestBase;
  
  public class LoginPage extends TestBase {
  
      //Page Factory - object repository:
  
          @FindBy(id = "li_myaccount")
          WebElement myaccountbtn;
  
          //*[@id="li_myaccount"]/ul/li[1]/a
  
          @FindBy(xpath = "//a[contains(text(), 'login')]")
          WebElement loginbtn;
  
          @FindBy(name = "username")
          WebElement username;
  
          @FindBy(name = "password")
          WebElement password;
  
          @FindBy(xpath = "//*[@id='loginfrm']/button")
          WebElement lgnbtn;
  
          @FindBy(xpath = "//a[contains(text(), 'Sign Up')]")
          WebElement Signupbtn;
  
          //Initialize the Page Objects
      public LoginPage() {
          PageFactory.initElements(driver, this);
      }
  
      //Actions
      public String ValidatePageTitle() {
          return driver.getTitle();
      }
  
  
      public HomePage login(String un, String pwd) {
  
          username.sendKeys(un);
          password.sendKeys(pwd);
          myaccountbtn.click();
          loginbtn.click();
  
      return new HomePage();
          }
  
      }`
  </code></pre>