以下是一個簡單的Java實現學生管理系統的代碼，使用ArrayList集合來存儲學生信息。

import java.util.ArrayList;
import java.util.Scanner;

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

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

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    public String getId() {
        return id;
    }
}

public class StudentManagementSystem {
    private ArrayList<Student> students;

    public StudentManagementSystem() {
        students = new ArrayList<>();
    }

    public void addStudent(Student student) {
        students.add(student);
    }

    public void removeStudent(String id) {
        for (int i = 0; i < students.size(); i++) {
            if (students.get(i).getId().equals(id)) {
                students.remove(i);
                break;
            }
        }
    }

    public void displayStudents() {
        for (Student student : students) {
            System.out.println("Name: " + student.getName());
            System.out.println("Age: " + student.getAge());
            System.out.println("ID: " + student.getId());
            System.out.println("------------------------");
        }
    }

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

        while (true) {
            System.out.println("1. Add Student");
            System.out.println("2. Remove Student");
            System.out.println("3. Display Students");
            System.out.println("4. Exit");
            System.out.print("Enter your choice: ");
            int choice = scanner.nextInt();

            switch (choice) {
                case 1:
                    System.out.print("Enter student name: ");
                    String name = scanner.next();
                    System.out.print("Enter student age: ");
                    int age = scanner.nextInt();
                    System.out.print("Enter student ID: ");
                    String id = scanner.next();
                    Student student = new Student(name, age, id);
                    system.addStudent(student);
                    break;
                case 2:
                    System.out.print("Enter student ID to remove: ");
                    String removeId = scanner.next();
                    system.removeStudent(removeId);
                    break;
                case 3:
                    system.displayStudents();
                    break;
                case 4:
                    System.exit(0);
                    break;
                default:
                    System.out.println("Invalid choice. Please try again.");
                    break;
            }
        }
    }
}

這個程序中，Student類表示學生，包含姓名、年齡和學號屬性。StudentManagementSystem類表示學生管理系統，包含一個ArrayList集合來存儲學生信息。

在main方法中，使用一個無限循環來接受用戶的輸入操作。用戶可以選擇添加學生、刪除學生、顯示學生列表或退出程序。根據用戶的選擇，調用StudentManagementSystem類中的相應方法來執行相應的操作。

注意：這只是一個簡單的示例，沒有進行輸入驗證和錯誤處理。在實際使用中，可能需要添加更多的功能和邏輯來滿足實際需求。