Question

1.i just wanted to know can i start the the service without creating activity in android. if yes why ? or if not then why not?

1. can i put my service creation code in oncreate method directaly?
2. Difference between Polymorphism and interface in java?

Answer 1

ofcourse you can start a service without activity (like something in a receiver class)

eg

    public class MyStartServiceReceiver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
    Log.d("", "in start service");
    Intent service = new Intent(context, rs.class);
    context.startService(service);
}
  } 

and an interface is a class that is not fully defined ie: there wont be any concrete methods in it something like abstract class but an abstract class can contain concrete methods where as an interface cannot