Bidirectional ManyToMany infinite recursion - spring

Question

I am using spring boot and spring data rest and have two entities, Exam and Subject which are defined as follows:
public class Exam {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name="exam_id")
Integer examId;
#Column(name="exam_name")
String examName;
#ManyToMany(mappedBy = "exams")
Set<Subject> subjects = new HashSet<>(0);
}
public class Subject {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "subject_id")
Integer subjectId;
#Column(name = "subject_name")
String subjectName;
#ManyToMany
#JoinTable(
name = "subject_exam",
joinColumns = {#JoinColumn(name = "subject_id", updatable = false, nullable = false)},
inverseJoinColumns = {#JoinColumn(name = "exam_id", updatable = false, nullable = false)}
)
Set<Exam> exams = new HashSet<>(0);
}
Now I have defined projection for subject as follow:
#Projection(name="detail", types={Subject.class})
public interface SubjectDetailProjection {
Integer getSubjectId();
String getSubjectName();
Set<ExamDetailProjection> getExams();
}
Detail projection for exam has also been defined in the same manner.
Now I am getting infinite recursion when calling api for this projection. How can I avoid this issue?

Answer 1

You have to delete, in your ExamDetailProjection, your referente to Subject.
You must to define one package of projections to your Subject and another package of projections to your Exams.
The exam projection will have a subject projection without reference to exam and the same in the other direction.