Mapeamento ManyToMany com JPA

Estudante.java

@Entity
@Table(name = "estudantes")
public class Estudante {
  
  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Long id;
  private String nome;
  //outros atributos...
  
  @ManyToMany(cascade = {CascadeType.PERSIST, CascadeType.MERGE})
  @JoinTable(name = "matriculas", 
             joinColumns = @JoinColumn(name = "estudante_id"), 
             inverseJoinColumns = @JoinColumn(name = "turma_id")
  )
  private Set<Turma> matriculas = new HashSet<>();
  
  public void registrarMatricula(Turma turma) {
    matriculas.add(turma);
    turma.getMatriculas().add(this);
  }
  
  public void removerMatricula(Turma turma) {
    matriculas.remove(turma);
    turma.getMatriculas().remove(this);
  }
  
  //getters, setters, equals, hashCode, etc.
}

Turma.java

@Entity
@Table(name = "turmas")
public class Turma {
  
  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Long id;
  private String codigo;
  //outros atributos...
  
  @ManyToMany(mappedBy = "matriculas")
  private Set<Estudante> matriculas = new HashSet<>();
  
  //getters, setters, equals, hashCode, etc.
}