java - Id with null value in return with mongoDB -

@mongoobjectid annotation added insert objectid in database, when data contained in collection return null id. ids , values ​​aren't null.
how id correctly?

my entity

import org.jongo.marshall.jackson.oid.mongoobjectid;  import java.io.serializable; import java.util.list; import java.util.map; import java.util.stream.collectors;  public class instancia implements serializable {      @mongoobjectid     string id;     string instancia;     string categoria;     string dono;     string data_criacao;     string descricao;     boolean ativo;     map<string, boolean> servicos;      public string getid() {         return this.id;     }      public instancia setid(string id) {         this.id = id;         return this;     }      public string getinstancia() {         return this.instancia;     }      public instancia setinstancia(string instancia) {         this.instancia = instancia;         return this;     }      public string getcategoria() {         return this.categoria;     }      public instancia setcategoria(string categoria) {         this.categoria = categoria;         return this;     }      public string getdono() {         return this.dono;     }      public instancia setdono(string dono) {         this.dono = dono;         return this;     }      public string getdata_criacao() {         return this.data_criacao;     }      public instancia setdata_criacao(string data_criacao) {         this.data_criacao = data_criacao;         return this;     }      public string getdescricao() {         return this.descricao;     }      public instancia setdescricao(string descricao) {         this.descricao = descricao;         return this;     }      public boolean getativo() {         return this.ativo;     }      public instancia setativo(boolean ativo) {         this.ativo = ativo;         return this;     }      public boolean isservicoenabled(string servico) {         boolean b = this.servicos.get(servico);         if(b == null){             b = false;         }         return b;     }      public list<string> getservicosenabled(){         list<string> servicos = this.servicos.keyset().stream().filter((me) -> {             boolean b = this.servicos.get(me);             if(b == null){                 b = false;             }             return b;         }).collect(collectors.tolist());         return servicos;     }   } 

how trying use oid

instancia instance = new instancia(); instances.find(withoid(instance.id)).as(instancia.class);