In my application, Vibration mode not working above 4.0 version?

My code is,

```
 final Vibrator vibe = (Vibrator)
 this.context.getSystemService(Context.VIBRATOR_SERVICE);
 vibe.vibrate(800);

```

CAn any please help me to sort it out. Thanks in advance

In manifest

```
<uses-permission android:name="android.permission.VIBRATE" />

```