Payroll with Inheritance and Method Overriding

/*
 * Problem : Process commands line by line.
 * Input   : Several lines.
 * Output  : Pay lines and a total.
 * Approach: Parent class and an overriding child.
 * Time    : O(n)
 * Space   : O(n)
 * Java    : 8 or newer.
 */
import java.util.Scanner;

public class Main {
        // Step 1: The parent class holds the base pay. Pay is the base amount by default.
        static class Staff {
            protected final String name;
            protected final long base;

            Staff(String name, long base) {
                this.name = name;
                this.base = base;
            }

            long pay() {
                return base;
            }
        }

        // Step 2: A manager gets the base pay plus a bonus. It replaces (overrides) pay().
        static class Manager extends Staff {
            private final long bonus;

            Manager(String name, long base, long bonus) {
                super(name, base);
                this.bonus = bonus;
            }

            @Override
            long pay() {
                return super.pay() + bonus;
            }
        }

    // This method solves the task. It receives the input and returns the answer.
    static String[] solve(String[] lines) {
        java.util.List<Staff> people = new java.util.ArrayList<>();
        for (String line : lines) {
            String[] parts = line.split(" ");

            // Step 3: Make a Manager for a manager line. Other lines are plain Staff.
            if (parts[0].equals("manager")) {
                people.add(new Manager(parts[1], Long.parseLong(parts[2]), Long.parseLong(parts[3])));
            } else {
                people.add(new Staff(parts[1], Long.parseLong(parts[2])));
            }
        }

        // Step 4: Call pay() on each person. Java picks the right version at run time.
        String[] output = new String[people.size() + 1];
        long total = 0;
        for (int i = 0; i < people.size(); i++) {
            long amount = people.get(i).pay();
            output[i] = people.get(i).name + " " + amount;
            total += amount;
        }
        output[people.size()] = "Total " + total;
        return output;
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        java.util.List<String> all = new java.util.ArrayList<>();
        while (scanner.hasNextLine()) {
            String line = scanner.nextLine().trim();
            if (!line.isEmpty()) {
                all.add(line);
            }
        }
        String[] lines = all.toArray(new String[0]);
        System.out.println(String.join("\n", solve(lines)));
    }
}