类之间互相引用

请教各位大神：如果定义了两个类，怎样让彼此都持有对方的引用呢？

public class Student{

private String name;

private Teacher tea;

public void setTeacher(Teacher t){

tea=t;

}

}

public class Teacher{

private String name;

private Student stu;

public void setStudent(Student s){

stu=s;

}

}

public class Test{

@Test

public void fun(){

Student s1=new Student();

Teacher t1=new Teacher();

各位大神，在这里怎么样让s1持有t1的引用，t1持有s1的引用呢？谢谢了先

}

}