Message Title

in Parent:
    @ManyToMany(fetch = FetchType.LAZY, targetEntity = Child.class, cascade = CascadeType.MERGE)
    private List<Child> children;

In Child:
    @ManyToMany(fetch = FetchType.LAZY, targetEntity = Parent.class, cascade = CascadeType.MERGE)
    private List<Parent> parents;

seems to work fine. However, as soon as I add the @JoinTable it does insert it twice:

in Parent:
    @ManyToMany(fetch = FetchType.LAZY, targetEntity = Child.class, cascade = CascadeType.MERGE)
    @JoinTable(name = "parent_child", joinColumns = @JoinColumn(name = "parent_id"), inverseJoinColumns = @JoinColumn(name = "child_id"))
    private List<Child> children;

In Child:
    @ManyToMany(fetch = FetchType.LAZY, targetEntity = Parent.class, cascade = CascadeType.MERGE)
    @JoinTable(name = "parent_child", joinColumns = @JoinColumn(name = "child_id"), inverseJoinColumns = @JoinColumn(name = "parent_id"))
    private List<Parent> parents;