Frozen POJO Concept

public interface DomainFirst {

  interface Factory {
  
    Data newData();
    Pojo newPojo();
  }
 
  interface Data extends Factory { // read-only
  
    int getId();
    String getName(); 
  }
 
  interface Pojo extends Data { // read-write
  
    Pojo setId(int id);
    Pojo setName(String name);
  }

}


public interface DomainSecond {

  interface Factory {
  
    Data newData();
    Pojo newPojo();
  }
 
  interface Data extends Factory { // read-only
  
    int getId();
    String getName();
    DomainFirst.Data getDomainFirst();
  }
 
  interface Pojo extends Data { // read-write
  
    Pojo setId(int id);
    Pojo setName(String name);
    DomainFirst.Pojo setDomainFirst();
  }

}

public static void main(String[] args) {
  
    DomainSecond.Pojo pojo2 = ...;
    DomainSecond.Data data2 = pojo2.setId(2).setName("pojo2").newData();
    //
    DomainFirst.Data data = pojo2.setDomainFirst().setId(1).setName("pojo1").newData();
    DomainFirst.Pojo pojo = data.newPojo(); 
}