Why are setters bad at interfaces?

Question

Why do setters work poorly in interfaces if we talk about domain objects?

Clarification:

I have a domain object that is stored in db. It has several fields that are very expensive. I.e.

class JurasicPark {

  private long area;

  ...other fields ...

  getters and setters

  ....

  private Collection<Dinosaur> dinosaurs;
  private Collection<ExoticTree> flora;

  public Collection<Dinosaur> getDinosaurus(){
      ...
  }

  public Collection<ExoticTree> getFlora(){
      ...
  }


}

Fields dinosaursand floravery expensive to initialize and install. But in many cases, I do not need these fields, which need to be set every time.

The problem is that if I go back to the custom instance of the JurasicPark class with dinosaursor flora, don't initialize it to populate the listing with either NPE or some kind of presentation that I throw away. I do not want the api user to think about this and remember which fields may not be set.

, , IJurasicPark IFullJurasicPark, , flora dinosaurs.

   interface IFullJurasicPark extends IJurasicPark

    class IJurasicPark implements IFullJurasicPark

IJurasicPark , , ?

LazyInit.

Answer 1

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Answer 2

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}

public void accelerate() {
    setSpeed(getSpeed() + 1);
}

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Can someone clarify what I'm saying, or am I mixing things up right now?

what i'm talking about in the code translates as:

Interface IBoard = new ActualBoard();