sort objects with comparable

package com.usr.collections;

public class Employee implements Comparable<Employee> {

       private String firstName;

       private String lastName;

       public Employee(String firstName, String lastName) {

              super();

              this.firstName = firstName;

              this.lastName = lastName;

       }

       public String getFirstName() {

              return firstName;

       }

       public String getLastName() {

              return lastName;

       }

       public int compareTo(Employee obj) {

              Employee e = (Employee) obj;

              return this.firstName.compareTo(e.getFirstName());

       }

}

package com.usr.collections;

import java.util.ArrayList;

import java.util.Collections;

import java.util.List;

public class ComparableTest {

       static List<Employee> empList = new ArrayList<Employee>();

       public static void main(String[] args) {

              empList.add(new Employee("Berry", "Alex"));

              empList.add(new Employee("Tony", "Blair"));

              empList.add(new Employee("Alex", "Berry"));

              empList.add(new Employee("Blair", "Tony"));

              displayEmpList(empList);

              System.out.println(".....................");

              Collections.sort(empList);

              System.out.println("After sorting");

              System.out.println("........................");

              displayEmpList(empList);

       }

       private static void displayEmpList(List<Employee> list) {

              for (Employee emp : empList) {

                     System.out.println(emp.getFirstName());

              }

       }

}

OUTPUT 

Berry
Tony
Alex
Blair
.....................
After sorting
........................
Alex
Berry
Blair
Tony