import java.util.ArrayList;
import java.util.Random;

class Test {

  public static void main(String args[]) {
    ArrayList<Employee> list = new ArrayList<>(); // make an empty list
    Random rn = new Random(); // random number generator
    // put 20 objects into list with random values
    for (int i = 0; i < 20; i++) {
      list.add(new Employee(rn.nextInt(100), rn.nextInt(100)));
    }
    // do a very simple bubble sort. Very inefficient but who cares
    for (int i = 0; i < list.size(); i++) {
      for (int j = 0; j < list.size() - 1; j++) {
        if (list.get(j).ID < list.get(j + 1).ID) { // sort on ID field
          Employee temp = list.get(j).copy(); // swap j and j+1
          list.set(j, list.get(j + 1));
          list.set(j + 1, temp);
        }
      }
    }
    // see what we've got
    for (int i = 0; i < list.size(); i++) {
      System.out.println(list.get(i));
    }
  }
}

class Employee {
  int ID, data;
  Employee(int ID, int data) {
    this.ID = ID;
    this.data = data;
  }
  Employee copy() {
    return new Employee(ID, data);
  }
  public String toString() {
    return ID + " : " + data;
  }
}