java何时使用抽象类以及何时使用接口

Question

Possible Duplicate:
When to use interfaces or abstract classes? When to use both?

<>考虑这个

public abstract class Flat
{
    //some properties


    public void livingRoom(){
       //some code
    }

    public void kitchen(){
       //some code
    }

    public abstract void bedRoom();

}
An implementation class would be as follows:

public class Flat101 extends Flat
{
        public void bedRoom() {
            System.out.println("This flat has a customized bedroom");
       }        

}

或者，我可以使用接口而不是抽象类来实现以下相同目的：

class Flat
{
  public void livingRoom(){ 
       System.out.println("This flat has a living room");
  }

  public void kitchen(){
     System.out.println("This flat has a kitchen");
 } 

}

interface BedRoomInterface
{
     public abstract void bedRoom();
}

public class Flat101 extends Flat implements BedRoomInterface
{
       public void bedRoom() {
      System.out.println("This flat has a customized bedroom");
       }
}

现在的问题是：对于这种设置，为什么要选择使用接口（或者）为什么要选择使用抽象类

Answer 1

通常说来，当您想要放置可在实现之间重用的公共逻辑时，请使用abstract类。否则，请使用Interface

还有一些例外，通常与设计模式密切相关。但要保持简单