I have a `User` class as below and I am trying to enforce validation and I am getting an: 

> 
> error cannot find symbol symbol: class Size
> 
> 
> 

My class looks something like this:

```
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class User {

    @Id
    private long id;
    @Size(min=1,max=18)
    private int age;

    // getters and setters

}

```