null pointer exception in selenium java WebDriver

Question

My code :

public class Testlogin {

    WebDriver driver;

    public Testlogin(WebDriver driver) {
        this.driver=driver;
    }

    WebElement userName = driver.findElement(By.id("username"));
    WebElement Password = driver.findElement(By.id("password"));
    WebElement login = driver.findElement(By.xpath("//button"));

    public void loginpages(String user,String pass) {
        userName.sendKeys(user);
        Password.sendKeys(pass);
        login.click();
    }
}

public class Testclass {

    public static void main(String[] args) {
        WebDriver driver = new FirefoxDriver(); 
        driver.get("https://the-internet.herokuapp.com/login");
        Testlogin test = new Testlogin(driver);
        test.loginpages("tomsmith","SuperSecretPassword!");
    }
}

Getting following error:

Exception in thread "main" java.lang.NullPointerException
    at Test.Testlogin.<init>(Testlogin.java:18)
    at Test.Testclass.main(Testclass.java:14)

In the testlogin class move all of the web elements to the top of the file, but only assign them in the constructor. — Aiden Grossman
– Aiden Grossman, Commented Apr 10, 2018 at 14:25
Like user iiiiiii pointed out in his answer (which should have been a comment) you shouldn't capitalise variable names. Always inform yourself about the naming conventions of a new language — Georg Plaz
– Georg Plaz, Commented Apr 10, 2018 at 14:41
You can also visit this helpful page that iiiiiii provided in her answer to review the naming convention for java — Georg Plaz
– Georg Plaz, Commented Apr 10, 2018 at 14:56
Possible duplicate of What is a NullPointerException, and how do I fix it? — JeffC
– JeffC, Commented Apr 10, 2018 at 18:01

Gambotic · Accepted Answer · 2018-04-10 14:39:17Z

1

the driver object has to be instatiated first. e.g. move it inside the constuctor:

public Testlogin(WebDriver driver)
{
    this.driver=driver;

    WebElement userName = driver.findElement(By.id("username"));
    WebElement Password = driver.findElement(By.id("password"));
    WebElement login = driver.findElement(By.xpath("//button"));

}

answered Apr 10, 2018 at 14:39

Gambotic

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2 Comments

Matt Over a year ago

You beat me by seconds nice

Gambotic Over a year ago

wlc - then you should accept the answer (stackoverflow.com/help/accepted-answer)

Matt · Accepted Answer · 2018-04-10 14:40:01Z

1

Make the testlogin class look like below if the driver is not yet set it will point to null and when you try to run driver.findElement(By.id("username")); and the driver is null this will not work to fix this do as Aiden Grossman said these will initialize when the driver is set

public class Testlogin {

    WebDriver driver;

    public Testlogin(WebDriver driver) {
        this.driver=driver;
        WebElement userName = driver.findElement(By.id("username"));
        WebElement Password = driver.findElement(By.id("password"));
        WebElement login = driver.findElement(By.xpath("//button"));
    }

    public void loginpages(String user,String pass) {
        userName.sendKeys(user);
        Password.sendKeys(pass);
        login.click();
    }
}

answered Apr 10, 2018 at 14:40

Matt

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1 Comment

Gambotic Over a year ago

you wrote more than me ;)

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