Here is an example that uses hashcode() and equal() method and store the employee information into hashmap and display it.

import java.util.*;
public class Employee {
private String firstname;
private String lastname;
public Employee(String firstname, String lastname){
this.firstname = firstname;
this.lastname = lastname;
}
public String getFirstname() {
        return firstname;
    }
    public String getLastname() {
        return lastname;
    }

public String toString() {
return lastname + ", " + firstname;
}
public int hashCode() {
return this.toString().hashCode();
}
public boolean equals(Object emp) {
if ( emp == null ) return false;
if ( this.getClass() != emp.getClass() ) return false;
String name = ((Employee)emp).toString();
return this.toString().equals(name);
}
public static void main(String[]args){
    HashMap<Integer,Employee> map = new HashMap<Integer,Employee>();
    map.put(1,new Employee("Annie","Smith"));
    map.put(2,new Employee("Angel","De'souza"));
    map.put(3,new Employee("John","Paul"));
    map.put(4,new Employee("Joe","Smith")); 
   for (Employee employee : map.values())
        {
    System.out.println(employee.toString());
        }

}
}