写出完整代码并且注释

在这个示例中，我会为你展示一个简单的Java代码片段，这是一个基于上述人事管理系统的例子，使用了继承和多态的概念。首先，我们定义一个通用的`PersonClass`，然后创建`TeacherClass`和`StudentClass`作为其子类。

// 定义通用人员类PersonClass
class PersonClass {
    private String id;
    private String name;
    private String gender;
    private Date birthDate;

    // 构造函数和getter/setter
    public PersonClass(String id, String name, String gender, Date birthDate) {
        this.id = id;
        this.name = name;
        this.gender = gender;
        this.birthDate = birthDate;
    }

    // getters and setters (省略)
    
    @Override
    public String toString() {
        return "Person [id=" + id + ", name=" + name + ", gender=" + gender + ", birthDate=" + birthDate + "]";
    }
}

// 定义教师类TeacherClass，继承自PersonClass
class TeacherClass extends PersonClass {
    private String department; // 部门
    private String title; // 职称
    private double salary; // 工资

    // 构造函数
    public TeacherClass(String id, String name, String gender, String department, String title, double salary) {
        super(id, name, gender, birthday); // 调用父类构造函数
        this.department = department;
        this.title = title;
        this.salary = salary;
    }

    // getters and setters (省略)

    // 用于演示多态性的toString方法
    @Override
    public String toString() {
        return "Teacher [" + super.toString() + ", department=" + department + ", title=" + title + ", salary=" + salary + "]";
    }
}

// 定义学生类StudentClass，继承自PersonClass
class StudentClass extends PersonClass {
    private int collegeScore; // 高考分数
    private String major; // 所学专业

    // 构造函数
    public StudentClass(String id, String name, String gender, String major, int collegeScore) {
        super(id, name, gender, birthday); // 调用父类构造函数
        this.major = major;
        this.collegeScore = collegeScore;
    }

    // getters and setters (省略)

    // 同样用于演示多态性的toString方法
    @Override
    public String toString() {
        return "Student [" + super.toString() + ", major=" + major + ", collegeScore=" + collegeScore + "]";
    }
}

// 在主类中测试
public class MainClass {
    public static void main(String[] args) {
        // 创建并打印TeacherClass对象
        TeacherClass teacher = new TeacherClass("T001", "张三", "男", "IT部", "教授", 5000);
        System.out.println(teacher);

        // 创建并打印StudentClass对象
        StudentClass student = new StudentClass("S001", "李四", "女", "数学系", 680);
        System.out.println(student);
    }
}

在这个例子中，`main`函数展示了如何创建`TeacherClass`和`StudentClass`的实例，并通过它们的`toString`方法展示了多态性，即虽然都是`PersonClass`类型的引用，但实际调用了对应子类的特定方法。注意，`super`关键字在这里用于调用父类的方法。