Try below code--
System.setProperty("webdriver.chrome.driver","
path of chromedriver.exe");
ChromeOptions options = new ChromeOptions();
options.addArguments("user-data-dir=C:/Users/
mention user name/AppData/Local/Google/Chrome/User Data/Default");
options.addArguments("--start-maximized");
WebDriver driver = new ChromeDriver(options);
driver.get("
https://mail.google.com");
Once browser open with gmail SignIn page then follow the following steps--
1. Type your username and password manually
2. Close the browser
3. run again the same code
Now you dont need to provide username and password again...:)
Note- Above code will work with window 7,8.
--Manoj Hans