用java代码写出：新建集合，把自己本组的同学加到集合中HashSet，Student ---->name age如果有重复自动覆盖2.删除自己同姓的同学，如 删除张的同学3.输出剩下的同学

以下是用 Java 代码实现的答案：

1. 新建集合，把自己本组的同学加到集合中 HashSet，Student ---->name age 如果有重复自动覆盖

HashSet<Student> students = new HashSet<>();
students.add(new Student("张三", 20));
students.add(new Student("李四", 21));
students.add(new Student("王五", 22));
students.add(new Student("张三", 23)); // 自动覆盖

其中，Student 类的定义如下：

class Student {
    String name;
    int age;

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

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof Student)) return false;
        Student student = (Student) o;
        return age == student.age &&
                Objects.equals(name, student.name);
    }

    @Override
    public int hashCode() {
        return Objects.hash(name, age);
    }
}

2. 删除自己同姓的同学，如删除张的同学

Iterator<Student> iterator = students.iterator();
while (iterator.hasNext()) {
    Student student = iterator.next();
    if (student.name.equals("张三")) {
        iterator.remove();
    }
}

3. 输出剩下的同学

for (Student student : students) {
    System.out.println(student.name + " " + student.age);
}

希望这个答案能够帮到你！