TestNG inheritance - eclipse is opening two tabs to execute the program

I am executing a testNG class giving an extension to other class. While executing,it opens a two diff tabs to execute the operation and unable to locate the similar xpath which i used in different normal class,but now enter code hereit is showing the error: org.openqa.selenium.NoSuchElementException: no such element: Unable to locate element: {"method":"xpath","selector":"/html/body/div[1]/div[1]/div[2]/ul[1]/li[1]/a"}

have tried with absolute and relative Xpath also,but the error is same

/

    /first class (base class)

        public class mlogin {
        public WebDriver driver;

        @Test 
        public void login() throws InterruptedException {

              driver.findElement(By.id("UserName")).sendKeys("Jose");
              driver.findElement(By.id("Password")).sendKeys("mick@1234");
              Thread.sleep(2000);

     driver.findElement(By.xpath("/html/body/div[2]/div/div/div/form/div/div/div/div/div[2]/div/div[2]/div[3]/div/input")).click();
      }
      @BeforeMethod
      public void beforeMethod() {

              System.setProperty("webdriver.chrome.driver", "E:\\jarfiles\\chromedriver.exe");
              driver = new ChromeDriver();

              driver.get(base URL);
              driver.manage().window().maximize();
    }}

      //second class

             public class branch_master extends mlogin{

        @Test 
            public void b_master() throws InterruptedException {
            driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);

            driver.findElement(By.xpath("/html/body/div[1]/div[1]/div[2]/ul[1]/li[1]/a")).click();
            Thread.sleep(2000);
    }}