Java Design Patterns Composite Patterns

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

interface Testable {
   public String test();
}

class Employee implements Testable {
   private String manager;
   private String deptName;
   private List<Testable> controls;

   Employee(String manager, String deptName) {
      this.manager = manager;
      this.deptName = deptName;
      controls = new ArrayList<Testable>();
   }// w  w w . ja  v a  2 s.  c  om

   public void Add(Employee teacher) {
      controls.add(teacher);
   }

   public void Remove(Employee teacher) {
      controls.remove(teacher);
   }

   public List<Testable> getControllingDepts() {
      return controls;
   }

   @Override
   public String test() {
      return (manager + " is the  " + deptName);
   }

}

public class Main {
   public static void main(String[] args) {
      Employee manager = new Employee("A", "Principal");

      Employee dev = new Employee("B", "Dev");

      Employee tester = new Employee("C", "Tester");

      Employee front = new Employee("Employee-1", "Front");
      Employee front2 = new Employee("Employee-2", "Font");

      Employee cseEmployee1 = new Employee("Employee-1", "Backend");
      Employee cseEmployee2 = new Employee("Employee-2", "Backend");
      Employee cseEmployee3 = new Employee("Employee-3", "Backend");

      manager.Add(dev);
      manager.Add(tester);

      dev.Add(front);
      dev.Add(front2);

      tester.Add(cseEmployee1);
      tester.Add(cseEmployee2);
      tester.Add(cseEmployee3);

      front.Add(null);
      front2.Add(null);

      cseEmployee1.Add(null);
      cseEmployee2.Add(null);
      cseEmployee3.Add(null);

      System.out.println(manager.test());
      List<Testable> hods = manager.getControllingDepts();
      for (int i = 0; i < hods.size(); i++) {
         System.out.println(hods.get(i).test());
      }

      List<Testable> mathEmployees = dev.getControllingDepts();
      for (int i = 0; i < mathEmployees.size(); i++) {
         System.out.println(mathEmployees.get(i).test());
      }

      List<Testable> cseEmployees = tester.getControllingDepts();
      for (int i = 0; i < cseEmployees.size(); i++) {
         System.out.println(cseEmployees.get(i).test());
      }
      tester.Remove(cseEmployee2);
      cseEmployees = tester.getControllingDepts();
      for (int i = 0; i < cseEmployees.size(); i++) {
         System.out.println(cseEmployees.get(i).test());
      }
   }
}