Spring DataJPA not saving 3rd tabledata to the database - database

Question

I have no problem with saving my entities to the database. However when I try to insert values into my 3rd many-to-many table, it simply doesn't do anything.
Here is my student entity;
#Table(name = "student", schema = "school")
public class Student {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private long studentId;
#Column(name = "name")
private String name;
#Column(name = "surname")
private String surname;
#ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
#JoinTable(name = "student_classroom", schema = "school")
private Collection<Classroom> classroom = new ArrayList<>();
#ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.PERSIST)
#JoinTable(name = "student_teacher",
joinColumns = {
#JoinColumn(name = "student_id", referencedColumnName = "studentId",
nullable = false, updatable = false)},
inverseJoinColumns = {
#JoinColumn(name = "teacher_id", referencedColumnName = "teacherId",
nullable = false, updatable = false)})
private Set<Teacher> teachers = new HashSet<>();
The teacher entity.
#Entity
#Table(name = "teacher", schema = "school")
public class Teacher {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private long teacherId;
#Column(name = "name")
private String name;
#Column(name = "surname")
private String surname;
#ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
#JoinTable(name = "teacher_classroom", schema = "school")
private Collection<Classroom> classroom = new ArrayList<>();
#ManyToMany(mappedBy = "teachers", fetch = FetchType.LAZY)
private Set<Student> students = new HashSet<>();
Here is my service method.
public void addTeacherToStudent(long teacherId, long studentId) {
Optional<Teacher> teacher = teacherRepository.findById(teacherId);
Optional<Student> student = studentRepository.findById(studentId);
student.get().getTeachers().add(teacher.get());
teacher.get().getStudents().add(student.get());
}
It has no problem saving the teachers and students in the sets in memory, however it doesn't reach the database. I have tried every annotation, didn't work.

Answer 1

Try adding this in Teacher entity
#ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
#JoinTable(
name = "student_teacher",
joinColumns = #JoinColumn(name = "teacher_id"),
inverseJoinColumns = #JoinColumn(name = "student_id")
)
private Set<Student> students = new HashSet<>();