java - Retrofit + Robospice JSON return POJO with Null for nested field -

in project use robospice+retrofit exchange data remoute server, work perfect 1 litle problem, - 1 of pojo objects have nested field null every time.

pojo class

public class snapshot {  @serializedname("records_count") private integer recordscount;  @serializedname("created") private string created;  @serializedname("modified") private string modified;  @serializedname("records") private records records;  @serializedname("database_id") private string databaseid;  @serializedname("revision") private integer revision;  @serializedname("size") private integer size;  public integer getrecordscount() {     return recordscount; }  public void setrecordscount(integer recordscount) {     this.recordscount = recordscount; }  public string getcreated() {     return created; }  public void setcreated(string created) {     this.created = created; }  public string getmodified() {     return modified; }  public void setmodified(string modified) {     this.modified = modified; }  public records getrecords() {     return records; }  public void setrecords(records records) {     this.records = records; }  public string getdatabaseid() {     return databaseid; }  public void setdatabaseid(string databaseid) {     this.databaseid = databaseid; }  public integer getrevision() {     return revision; }  public void setrevision(integer revision) {     this.revision = revision; }  public integer getsize() {     return size; }  public void setsize(integer size) {     this.size = size; } 

}

retrofit class

public class retrofitspiceservice extends retrofitgsonspiceservice {  private static final string tag = "retrofitspiceservice";  private static final string authorization_header = "authorization"; private static final string user_agent_header = "user-agent"; private static final string user_agent = "cloud api android client example/1.0";  @override protected string getserverurl() {     return "https://my.cloud-api.net"; }  @override public void oncreate() {     super.oncreate();     addretrofitinterface(datasyncapi.class); }  @override protected restadapter.builder createrestadapterbuilder() {      restadapter.builder builder = new restadapter.builder();      builder.setrequestinterceptor(new requestinterceptor() {          @override         public void intercept(requestfacade request) {              request.addheader(user_agent_header, user_agent);             request.addheader(authorization_header, sharedpreferencesmanager.getregistrationtoken(getapplicationcontext()));          }      });      builder.setendpoint(getserverurl());     builder.setconverter(getconverter());      return builder; } 

}

so, field records in snapshot class equal null, why?

did try add gson converter

gson gson = builder.setfieldnamingpolicy(fieldnamingpolicy.lower_case_with_underscores).create(); restadapter restadapter = new restadapter.builder() .setendpoint("http://localhost/api") .setconverter(new gsonconverter(gson)).build();