//Reading data from property file :

      String username = prop.getProperty("username");
      String password = prop.getProperty("password");
           @Test
public void testValidCredentials()  {
obj.loginAs("username","password");

driver.findElement(By.id("id1")).sendKeys(username);
    driver.findElement(By.id("id2")).sendKeys(password);
    driver.findElement(By.id("id3")).click();
    return new HomePage(driver);

obj.loginAs("username","password");

obj.loginAs(username,password);