jpa - Why the list of a object returned from hibernate is empty? -

well, i'm here again. in project work, have faced problem, sametimes solve way it. in manytomany relationship, don't know make it. when use find method of entitymanager , it's returned object, , if object has list of other objects, list come empty when saved object filled list.

the classes:

public class equipecategoria {      @id     @generatedvalue(strategy= generationtype.identity)     private integer id;     private esexo sexo;     private ecategoria categoria;     @manytoone(cascade = cascadetype.all)     @cascade(org.hibernate.annotations.cascadetype.delete_orphan)     private equipe equipe;     @onetoone(cascade = cascadetype.all)     @cascade(org.hibernate.annotations.cascadetype.delete_orphan)     private equipejogo equipejogo;     @manytomany(cascade = cascadetype.all)     @cascade(org.hibernate.annotations.cascadetype.delete_orphan)     private list<dirigente> dirigentes;     @onetomany(cascade = cascadetype.all)     @cascade(org.hibernate.annotations.cascadetype.delete_orphan)     private list<atleta> atletas;     @manytoone     private modalidade modalidade;     @manytoone     private prova prova;     // getters , setters } 

and

public class dirigente {      @id     @generatedvalue(strategy= generationtype.identity)     private integer id;     private string doc_prof;     private string nome;     private efuncao funcao; // efuncao     @manytomany(cascade = cascadetype.all)     @cascade(org.hibernate.annotations.cascadetype.delete_orphan)     private list<equipecategoria> equipes;     @manytoone     private equipe equipe;     // getters , setters } 

what can do?