1- Charge your mobile upto 70 percent.
2- Switch off your mobile.
3- Press & Hold Power+Volume up+Home to enter recovery mode.
4- Select Wipe Data through volume key and press Power to enter.
5- Choose Yes-delete all user data.
6- When Wiping is completed then reboot the system.
7- First boot will take more time than usual after hard reset.
8- Adjust the setting, now your mobile is free from pattern lock.