Hibernate - 一对多 - Getters / Setters问题

Question

当我为OneToMany属性编写getter / setter时，我的程序正在冻结。

我有这两个实体：

COMPETENCE_LEVEL

@Entity
@Table(name="competence_level")
public class CompetenceLevel {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(name="id_competence_level")
    private Long idCompetenceLevel;

    @ManyToOne
    @JoinColumn(name="id_competence")
    private Competence competence;

    @ManyToOne
    @JoinColumn(name="id_level")
    private Level level;

    @ManyToOne
    @JoinColumn(name="id_profil")
    private Profil profil;

    public CompetenceLevel() {
        super();
    }

    public CompetenceLevel(Competence competence, Level level, Profil profil) {
        super();
        this.competence = competence;
        this.level = level;
        this.profil = profil;
    }

    /**
     * @return the idCompetenceLevel
     */
    public Long getIdCompetenceLevel() {
        return idCompetenceLevel;
    }

    /**
     * @param idCompetenceLevel the idCompetenceLevel to set
     */
    public void setIdCompetenceLevel(Long idCompetenceLevel) {
        this.idCompetenceLevel = idCompetenceLevel;
    }

    /**
     * @return the competence
     */
    public Competence getCompetence() {
        return competence;
    }

    /**
     * @param competence the competence to set
     */
    public void setCompetence(Competence competence) {
        this.competence = competence;
    }

    /**
     * @return the level
     */
    public Level getLevel() {
        return level;
    }

    /**
     * @param level the level to set
     */
    public void setLevel(Level level) {
        this.level = level;
    }

    /**
     * @return the profil
     */
    public Profil getProfil() {
        return profil;
    }

    /**
     * @param profil the profil to set
     */
    public void setProfil(Profil profil) {
        this.profil = profil;
    }

}

COMPETENCE

@Entity
@Table(name="competence")
public class Competence {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(name="id_competence")
    private Long idCompetence;

    @Column(name="libelle")
    private String libelle;

    @OneToMany(mappedBy="competence", cascade=CascadeType.ALL)
    private List<CompetenceLevel> competenceLevels;

    public Competence() {
        super();
    }

    public Competence(String libelle) {
        super();
        this.libelle = libelle;
    }

    public Long getIdCompetence() {
        return idCompetence;
    }

    public void setIdCompetence(Long idCompetence) {
        this.idCompetence = idCompetence;
    }

    public String getLibelle() {
        return libelle;
    }

    public void setLibelle(String libelle) {
        this.libelle = libelle;
    }

    // ISSUE !!!
    public List<CompetenceLevel> getCompetenceLevels() {
        return competenceLevels;
    }

    // ISSUE !!!
    public void setCompetenceLevels(List<CompetenceLevel> competenceLevels) {
        this.competenceLevels = competenceLevels;
    }

}

为什么，如果我不评论COMPETENCE的getter / setter，我的应用程序'冻结了（我相信这是无限递归）？谢谢