I restarted service BIND several times and after sometime it is getting turned off. I reinstalled BIND , still it is getting turned off. Even I reinstalled Ubuntu 14.04 x64 Minimal and 14.04 x86 Minimal several time but still it is getting turned off.
I restarted it using command also "service named restart" but still it is getting turned off.
The current configuration is
Ubuntu 14.04 x64 Minimal
256 MB RAM
256 MB VSwap
50 GB Disk Space