Room database with one-to-much relation

Question

I have 2 Entities: Employee and Specialty. Every Employee can have some Specialties. POJOs are generated.

@Entity(indices = {@Index(value = {"f_name", "l_name", "birthday", 
"avatarLink"}, unique = false)}, inheritSuperIndices = true)
public class Employee implements Serializable {
@PrimaryKey(autoGenerate = true)
private int employeeId;
private String f_name;
private String l_name;
private String birthday;
@Ignore
private int age;
private String avatarLink;
@Embedded
private List<Specialty> specialty;
private final static long serialVersionUID = -8824149947485321362L;

@Ignore
public Employee() {
}

public Employee(int employeeId, String f_name, String l_name, String 
birthday, String avatarLink, List<Specialty> specialty) {
    this.employeeId = employeeId;
    this.f_name = f_name;
    this.l_name = l_name;
    this.birthday = birthday;
    this.avatarLink = avatarLink;
    this.specialty = specialty;
}

public int getEmployeeId() {
    return employeeId;
}

public void setEmployeeId(int employeeId) {
    this.employeeId = employeeId;
}
And some more setters\getters...

And Specialty

@Entity
public class Specialty implements Serializable {

@PrimaryKey
private int specId;
private String specName;
private final static long serialVersionUID = 4288061416169200241L;

public Specialty(int specId, String specName) {
    this.specId = specId;
    this.specName = specName;
}

@Ignore
public Specialty() {
}

public int getSpecId() {
    return specId;
}
    And some more setters\getters...

I have this error: error: Entities and Pojos must have a usable public constructor. You can have an empty constructor or a constructor whose parameters match the fields (by name and type).

I check so many questions and read docs, but it not helps me. Thank you

Answer 1

you should add @Ignore to serialVersionUID fields. In view of Room, it's just another column.

@Ignore
private final static long serialVersionUID = 4288061416169200241L;