import java.util.Comparator;
 import org.apache.commons.lang3.builder.CompareToBuilder;
 public class EmployeeComparator implements Comparator {

    @override
    public int compare(Employee e1, Employee e2){
           return new CompareToBuilder().append(e1.getFirstName(), e2.getFirstName())
                                        .append(e1.getLastName(), e2.getLastName())
                                        .append(e1.getSalary(), e2.getSalary())
                                        .append(e1.getAge() ,e2.getAge())
                                        .toComparison();
    }
 }