Java定义一个Person类，含：姓名、性别、年龄等字段；继承Person类设计Teacher类，增加：职称、部门等字段；继承Person类设计Student类，增加：学号、班级等字段。定义各类的构造方法和toString0方法，并分别创建对象进行测试。

这是一个关于Java编程的问题，我可以回答。

以下是代码示例：

public class Person {
    private String name;
    private String gender;
    private int age;

    public Person(String name, String gender, int age) {
        this.name = name;
        this.gender = gender;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public String getGender() {
        return gender;
    }

    public int getAge() {
        return age;
    }

    public String toString() {
        return "Name: " + name + "\n" +
               "Gender: " + gender + "\n" +
               "Age: " + age + "\n";
    }
}

public class Teacher extends Person {
    private String title;
    private String department;

    public Teacher(String name, String gender, int age, String title, String department) {
        super(name, gender, age);
        this.title = title;
        this.department = department;
    }

    public String getTitle() {
        return title;
    }

    public String getDepartment() {
        return department;
    }

    public String toString() {
        return super.toString() +
               "Title: " + title + "\n" +
               "Department: " + department + "\n";
    }
}

public class Student extends Person {
    private int studentId;
    private String className;

    public Student(String name, String gender, int age, int studentId, String className) {
        super(name, gender, age);
        this.studentId = studentId;
        this.className = className;
    }

    public int getStudentId() {
        return studentId;
    }

    public String getClassName() {
        return className;
    }

    public String toString() {
        return super.toString() +
               "Student ID: " + studentId + "\n" +
               "Class Name: " + className + "\n";
    }
}

// 测试代码
public class Main {
    public static void main(String[] args) {
        Person person = new Person("Tom", "Male", 20);
        Teacher teacher = new Teacher("John", "Male", 30, "Professor", "Computer Science");
        Student student = new Student("Lily", "Female", 18, 1001, "Class A");

        System.out.println(person.toString());
        System.out.println(teacher.toString());
        System.out.println(student.toString());
    }
}

运行以上代码，输出如下：

Name: Tom
Gender: Male
Age: 20

Name: John
Gender: Male
Age: 30
Title: Professor
Department: Computer Science

Name: Lily
Gender: Female
Age: 18
Student ID: 1001
Class Name: Class A