Employee Salary System

Employee.java

public class Employee {

    private final int id;
    private final String name;
    private double salary;

    public Employee(int id, String name, double salary) {
        this.id = id;
        this.name = name;
        this.salary = salary;
    }

    public int getId() {
        return id;
    }

    public void increaseSalary(double percentage) {
        salary += salary * percentage / 100.0;
    }

    @Override
    public String toString() {
        return id + ", " + name + ", " + String.format("%.2f", salary);
    }

}

EmployeeApplication.java

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.function.Predicate;

public class EmployeeApplication {

    public static List<Employee> employees = new ArrayList<>();

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        print("Insert the number of workers:");
        int workers = scanner.nextInt();

        for (int i = 1; i <= workers; i++) {
            print("Employee #" + i + ":");

            print("Insert the id of the worker:");
            int id = scanner.nextInt();

            Employee employeeById = findEmployeeById(id);
            if (employeeById != null) {
                print("The id already exists");
                continue;
            }

            scanner.nextLine();

            print("Insert the name of the worker:");
            String name = scanner.nextLine();

            print("Insert the salary:");
            double salary = scanner.nextDouble();

            employees.add(new Employee(id, name, salary));
        }

        print("Insert the id of the worker to increase the salary:");
        int id = scanner.nextInt();

        Employee employeeById = findEmployeeById(id);
        if (employeeById == null) {
            print("The id does not exist");
            return;
        }

        print("Insert the percentage to increase the salary:");
        double percentage = scanner.nextInt();

        employeeById.increaseSalary(percentage);

        print("List of employees:");
        employees.forEach(System.out::println);
    }

    public static Employee findEmployeeById(int id) {
        return findEmployee(employee -> employee.getId() == id);
    }

    public static Employee findEmployee(Predicate<Employee> predicate) {
        return employees.stream()
                .filter(predicate)
                .findFirst()
                .orElse(null);
    }

    public static void print(String message) {
        System.out.println(message);
    }

}