how can I list array of array of object on jasper report by using modal

Question

shifts[
  {
   shift: "I",
   employees:[
     {
       id:"1"
       firstName:"Phong"
     },
     {
       id:"2"
       firstName:"Mann"
     }]
   },

   {
     shift: "II",
     employees:[
     {
       id:"23"
       firstName:"ABC"
     },
     {
       id:"32"
       firstName:"TRS"
     }]
   }

]}]

This Data I get from Modal Class

public class RosterModel {

  @JsonProperty(value = "shifts")
  private List<RosterShift> shifts;
}

public class RosterShift {


@JsonProperty(value = "shift")
    
    private String shift;
    
    @JsonProperty(value = "employees")
    private List<RosterEmployee> employees;
}

public class RosterEmployee {  
  
    @JsonProperty(value = "id")
    private String id;    
    @JsonProperty(value = "firstName")
    private String firstName;
}

Example that I have modal like this and this I want print this data on jasper report

Shift I
1	Phong
2	Mann
Shift II
23	ABC
32	TRS

This is what I want and I using

<field name="shifts.employees.firstName" class="java.util.List"/>

Please Help me to do this one sorry for my mistake I am new jasper