Java:将属性从一个对象实例复制到另一个对象实例？

Question

说你有

public class Car{
  private Engine m_eng;
  public Car(){

  }

  public Engine getEngine(){
    return m_eng;
  }

  public void setEngine(Engine engine){
    m_eng = engine;
  }
}

public class Engine{
  private String m_name;
  public Engine(){};
  public Engine(String name){ m_name = name;}

  public String getName(){
    return m_name;
  }
  public void setName(String name){
    m_name = name;
  }
}

public static void main(String[] args){
  Engine eng1 = new Engine("abc");
  Car car1 = new Car();
  car1.setEngine(eng1);
  Car car2 = new Car();
  car2.setEngine(car1.getEngine());
}

问题:car1 和 car2 的引擎是否指的是同一个 Engine 实例，或者当我执行 car2.setEngine(car1.getEngine()) 时，它会自动对 car1 进行深度复制.getEngineer() 并设置为 car2 ？

Answer 1

car1---------------->eng1

car2.setEngine(car1.getEngine());

结果

car1---------------->eng1 <----------------car2

从而指向同一个引擎实例