Два конструктора из одного класса

public class Employee {
 
    private String position;
    private String firstName;
    private String lastName;
    private int salary;
}

package ch10;
 
/**
 *
 */
public class Employee {
 
    private String position;
    private String firstName;
    private String lastName;
    private int salary;
 
    public Employee() {
    }
 
    public Employee(String firstName, String lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }
 
    public Employee(String firstName, String lastName, String position, int salary) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.position = position;
        this.salary = salary;
    }
 
    public String getFirstName() {
        return firstName;
    }
 
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
 
    public String getLastName() {
        return lastName;
    }
 
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
 
    public String getPosition() {
        return position;
    }
 
    public void setPosition(String position) {
        this.position = position;
    }
 
    public int getSalary() {
        return salary;
    }
 
    public void setSalary(int salary) {
        this.salary = salary;
    }
 
    @Override
    public String toString() {
        return "Employee{" +
                "firstName='" + firstName + '\'' +
                ", lastName='" + lastName + '\'' +
                ", position='" + position + '\'' +
                ", salary=" + salary +
                '}';
    }
 
    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
 
        Employee employee = (Employee) o;
 
        if (salary != employee.salary) return false;
        if (position != null ? !position.equals(employee.position) : employee.position != null) return false;
        if (!firstName.equals(employee.firstName)) return false;
        return lastName.equals(employee.lastName);
 
    }
 
    @Override
    public int hashCode() {
        int result = position != null ? position.hashCode() : 0;
        result = 31 * result + firstName.hashCode();
        result = 31 * result + lastName.hashCode();
        result = 31 * result + salary;
        return result;
    }
}

package ch10;
 
/**
 *
 */
public class EmployeeDemo {
    public static void main(String[] args) {
        Employee employee = new Employee("Joe", "Doe");
        employee.setPosition("CEO");
        employee.setSalary(150000);
 
        System.out.println(employee);
    }
}