import java.util.ArrayList;
import java.util.List;

public class Main {
	
	public static void main(String[] args) {
		Main m = new Main();
		List<String> names = m.executeCommand(new GetNamesCommand());
		System.out.println(names);
	}
	
	private <R> R executeCommand(Command<R> command) {
		return command.execute();
	}
}

abstract class Command<R> {
	
	public abstract R execute();
}

class GetNamesCommand extends Command<List<String>> {
	
	public List<String> execute() {
		List<String> names = new ArrayList<String>();
		names.add("one");
		names.add("two");
		names.add("three");
		return names;
	}
	
}