It's not a big deal in tests, but all fields in Java should be ``private``. In fact, you'll find this construct the most appropriate:

```java
public class XXX {
    private final UUID id;
    
    XXX(UUID id) {
        this.id = id;
    }

    ...
}
```

Having a ``final`` field will give a compile-time error if you ever forget to assign it.