Gmail improve security awareness for user by adding new feature : 2 factor authentication. This is abosultely not a new feature. Google has implemented this feature since a year ago. But there is a problem for some android user (like me), that related with this featyre. After activated 2 factor authentication in Gmail, i fail to login to the gmail account in my android handset. The error message say that i have entered wrong username or password. To solve this problem, you have to go to your account setting : https://www.google.com/settings/
In the Security Field, there is a 2-step Verification column, and then click edit.
Google will lead you to this page –> https://accounts.google.com/b/0/SmsAuthConfig
Scroll, and you can see the Option : Application-spesific Password
Click Option Manage Application-spesific password
Scroll and you can find a column named : Generate new application-specific password
You can see the bos for example Android, and then click Generate Password
Google will provide 16 digit random letter. That random letter is your password for your Google Accont in your Android Handset.
Finish. Now you can use your Google account in your android handset
Good Luck. :D