I just want to know can my own design server communicate directly with mobile appication (Android ,IOS ,BB). I need to send some information in XML form to the app. Regards
It works the other way around, a client contacts a server. So some sort of polling mechanism is required. Although it's possible with node.js I think, but have no experience with it.
pritaeas is correct, the app always needs to initiate the connection to the server before the server can send data to it. The only exception to this would be using a Push Notification system in the Android platform similar to iOS. This would be where your server sends a message to a service on the device/handset and not the client app. Example: https://parse.com/tutorials/android-push-notifications
Implementations such as that result in the background service listening for messages from the remote gateway/api which your server is communicating with also.
You could also tie in the Google Cloud Messaging (GCM) service: http://developer.android.com/google/gcm/index.html