Open Android Application at StartUp of Mobile.

To Start your application on startup of device.

First we have to create a BroadcastReceiver which will be started when boot completes as

public class MyService extends BroadcastReceiver
{

    @Override
    public void onReceive(Context context, Intent intent) {

        String action = intent.getAction();

        if(action.equalsIgnoreCase("android.intent.action.BOOT_COMPLETED"))
        {
            Intent myIntent=new Intent(context,package.YourActivity.class);
            myIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            context.startActivity(myIntent);
        }
}   

onRecieve will be first called when the BroadcastReceiver MyService starts.

Next make an entry of this receiver in AndroidManifest.xml

<receiver android:name=".MyService"
        android:enabled="true" >

            <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED" />
                 <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
</receiver>

Here in intent filter we have declared the action as android.intent.action.BOOT_COMPLETED ,
so that this receiver and intent with action android.intent.action.BOOT_COMPLETED

Now this receiver will be intimated when boot completes