Java задание с кодом, его нужно дополнить

Нужно выполнить задание. Дополнить код, который я закинула

Functional programming

Create a hierarchy of classes for storing information about human resources of a company based on the provided class skeletons.

Create a 3-level hierarchy composed of at least 20 different employees of all the kinds (i.e. trainees, workers and managers). Please note that only a manager can have subordinates.

Using functional programming features available since Java 8 please deliver the following functionality:

1. preparing payroll for all the employees;

2. preparing payroll for subordinates of the given manager;

3. calculating the total cost of bonuses;

4. searching for an employee with the longest seniority;

5. searching for the highest salary without bonus (a number should be returned);

6. searching for the highest salary with bonus (a number should be returned);

7. searching for employees whose surnames begin with ‘A’ subordinates of the given manager;

8. Searching for employees who earn more than 1000 PLN.