Java HashMap Example: Student Management with HashMap

public class Student {
    private String id;
    private String name;
    private int age;

    public Student(String id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    public Student() {}

    public String getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public String toString() {
        return 'ID: ' + id + ', Name: ' + name + ', Age: ' + age;
    }
}

import java.util.HashMap;

public class HashMapTest {
    public HashMapTest() {
        HashMap<String, Student> students = new HashMap<>();
        students.put('17H002', new Student('17H002', '孙悟空', 2000));
        students.put('17H001', new Student('17H001', '唐僧', 40));
        students.put('17H003', new Student('17H003', '猪八戒', 1000));
        students.put('17H004', new Student('17H004', '沙僧', 900));

        System.out.println(students.get('17H003'));
        System.out.println('All Students:');
        for (Student s : students.values()) {
            System.out.println(s);
        }

        students.remove('17H001');

        Student[] studentArray = students.values().toArray(new Student[0]);
        System.out.println('Student Array:');
        for (Student s : studentArray) {
            System.out.println(s);
        }
    }

    public static void main(String[] args) {
        HashMapTest test = new HashMapTest();
    }
}