考试信息系统经过分析具有如下类及相关属性、方法，并编写演示程序。 ‍ ‎（1）类名分别为：User, Student， Teacher，HeadTeacher，Exam,StudentExam； ‍ ‎（2）User是Student与Teacher的父类；Teacher是HeadTeacher的父类； ‍ ‎（3）User类的属性有：id, name, password, tel;方法：登录login，修改密码modifyPassword，获取用户id,name,tel信息getInfo; ‍ ‎（4）Student类属性：继承User的属性，平均分average,对象个数count; 方法：继承方法，考试test(Exam exam), 查询自己的成绩queryGrade(Exam exam); ‍ ‎（5）Teacher类属性：继承User的属性，职称professionalTitle; 方法：继承方法，出试卷test(Exam exam), 查询学生考试成绩queryGrade(Exam exam)，查询指定学生成绩queryGrade( Exam exam,Student stu)。 ‍ ‎（6）HeadTeacher（班主任）：继承Teacher的属性，职称professionalTitle; 方法：继承方法，查询自己班里学生考试成绩queryGrade(Exam exam，String clazz)。 ‍ ‎（7）Exam类属性：考试编号id，考试名称name，考试内容content，考试时间examDate;方法： 计算平均分getAverage()。 ‍ ‎（8）StudentExam类属性：学生stu，考试exam，成绩score。 ‍ ‎（9）每个类都有构造方法，访问器方法，toString()方法。

这是一个很完整的考试信息系统的类结构设计，需要根据需求编写对应的Java代码。以下是一个简单的示例代码：

// User类
public abstract class User {
    private String id;
    private String name;
    private String password;
    private String tel;

    public User(String id, String name, String password, String tel) {
        this.id = id;
        this.name = name;
        this.password = password;
        this.tel = tel;
    }

    public String getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public String getPassword() {
        return password;
    }

    public void modifyPassword(String password) {
        this.password = password;
    }

    public String getTel() {
        return tel;
    }

    public abstract void login();

    public abstract String getInfo();

    @Override
    public String toString() {
        return "User{" +
                "id='" + id + '\'' +
                ", name='" + name + '\'' +
                ", password='" + password + '\'' +
                ", tel='" + tel + '\'' +
                '}';
    }
}

// Student类
public class Student extends User {
    private double average;
    private int count;

    public Student(String id, String name, String password, String tel) {
        super(id, name, password, tel);
        this.average = 0;
        this.count = 0;
    }

    public double getAverage() {
        return average;
    }

    public void test(Exam exam) {
        // 考试操作
    }

    public double queryGrade(Exam exam) {
        // 查询成绩操作
        return 0;
    }

    @Override
    public void login() {
        // 登录操作
    }

    @Override
    public String getInfo() {
        // 获取用户信息操作
        return null;
    }

    @Override
    public String toString() {
        return "Student{" +
                "id='" + getId() + '\'' +
                ", name='" + getName() + '\'' +
                ", password='" + getPassword() + '\'' +
                ", tel='" + getTel() + '\'' +
                ", average=" + average +
                ", count=" + count +
                '}';
    }
}

// Teacher类
public class Teacher extends User {
    private String professionalTitle;

    public Teacher(String id, String name, String password, String tel, String professionalTitle) {
        super(id, name, password, tel);
        this.professionalTitle = professionalTitle;
    }

    public void test(Exam exam) {
        // 出试卷操作
    }

    public double queryGrade(Exam exam) {
        // 查询学生考试成绩操作
        return 0;
    }

    public double queryGrade(Exam exam, Student stu) {
        // 查询指定学生成绩操作
        return 0;
    }

    @Override
    public void login() {
        // 登录操作
    }

    @Override
    public String getInfo() {
        // 获取用户信息操作
        return null;
    }

    @Override
    public String toString() {
        return "Teacher{" +
                "id='" + getId() + '\'' +
                ", name='" + getName() + '\'' +
                ", password='" + getPassword() + '\'' +
                ", tel='" + getTel() + '\'' +
                ", professionalTitle='" + professionalTitle + '\'' +
                '}';
    }
}

// HeadTeacher类
public class HeadTeacher extends Teacher {
    public HeadTeacher(String id, String name, String password, String tel, String professionalTitle) {
        super(id, name, password, tel, professionalTitle);
    }

    public double queryGrade(Exam exam, String clazz) {
        // 查询自己班里学生考试成绩操作
        return 0;
    }

    @Override
    public String toString() {
        return "HeadTeacher{" +
                "id='" + getId() + '\'' +
                ", name='" + getName() + '\'' +
                ", password='" + getPassword() + '\'' +
                ", tel='" + getTel() + '\'' +
                ", professionalTitle='" + professionalTitle + '\'' +
                '}';
    }
}

// Exam类
public class Exam {
    private String id;
    private String name;
    private String content;
    private Date examDate;

    public Exam(String id, String name, String content, Date examDate) {
        this.id = id;
        this.name = name;
        this.content = content;
        this.examDate = examDate;
    }

    public double getAverage() {
        // 计算平均分操作
        return 0;
    }

    @Override
    public String toString() {
        return "Exam{" +
                "id='" + id + '\'' +
                ", name='" + name + '\'' +
                ", content='" + content + '\'' +
                ", examDate=" + examDate +
                '}';
    }
}

// StudentExam类
public class StudentExam {
    private Student stu;
    private Exam exam;
    private double score;

    public StudentExam(Student stu, Exam exam, double score) {
        this.stu = stu;
        this.exam = exam;
        this.score = score;
    }

    @Override
    public String toString() {
        return "StudentExam{" +
                "stu=" + stu +
                ", exam=" + exam +
                ", score=" + score +
                '}';
    }
}

以上仅为示例代码，具体实现需要根据实际需求进行调整。