Web Driver throws nullpointer exception while trying to find Element in my application

Question

public class Loginpage {

public  WebDriver driver;


    By uname = By.xpath("//*[@id='UserName']");
    By nextbutton = By.id("btnNext");
    By passw = By.id("Password");
    By signinbtn = By.id("btnSubmit");


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

    }

    public void setUserName(String uid ,String pass){

        driver.findElement(uname).sendKeys(uid);
        driver.findElement(nextbutton).click();
        driver.findElement(passw).sendKeys(pass);
        driver.findElement(signinbtn).click();

}
}

[RemoteTestNG] detected TestNG version 6.14.2 Starting ChromeDriver 2.38.552522 (437e6fbedfa8762dec75e2c5b3ddb86763dc9dcb) on port 23334 Only local connections are allowed. Sep 20, 2018 4:24:48 PM org.openqa.selenium.remote.ProtocolHandshake createSession INFO: Detected dialect: OSS java.lang.NullPointerException at Testrun.Loginpage.setUserName(Loginpage.java:24) at Testrun.Logintopage.validlogin(Logintopage.java:22) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:124) at org.testng.internal.Invoker.invokeMethod(Invoker.java:580) at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:716) at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:988) at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:125) at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:109) at org.testng.TestRunner.privateRun(TestRunner.java:648) at org.testng.TestRunner.run(TestRunner.java:505) at org.testng.SuiteRunner.runTest(SuiteRunner.java:455) at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:450) at org.testng.SuiteRunner.privateRun(SuiteRunner.java:415) at org.testng.SuiteRunner.run(SuiteRunner.java:364) at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52) at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:84) at org.testng.TestNG.runSuitesSequentially(TestNG.java:1208) at org.testng.TestNG.runSuitesLocally(TestNG.java:1137) at org.testng.TestNG.runSuites(TestNG.java:1049) at org.testng.TestNG.run(TestNG.java:1017) at org.testng.remote.AbstractRemoteTestNG.run(AbstractRemoteTestNG.java:114) at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:251) at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:77)

@Test
  public void validlogin() throws InterruptedException {

      try{
      WebDriver driver = new ChromeDriver();
          //this.driver = new ChromeDriver();
      driver.get("https://qa.reventics.com/REVCDIUTROP_PROD/");
      driver.manage().window().maximize();
      Thread.sleep(2000);
      Loginpage login = new Loginpage(driver);

     login.setUserName("George", "Reventics@1");

      }catch (Exception e) {
          e.printStackTrace();

    }

Answer 1

Your assignment doesn't look proper (there might be other problems which I did not look at). Instead of:

driver = this.driver;

You need to use

this.driver = driver

Answer 2

May be find elements is taking time to the element path better use implicit or explicit wait condition so it will wait till it will the path of the element you have given.

For me it worked in one senior