Nested Classes

Why Use Nested Classes?

There are several compelling reasons for using nested classes, among them:

• It is a way of logically grouping classes that are only used in one place.
• It increases encapsulation.
• Nested classes can lead to more readable and maintainable code.

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Java Gossip: 內部類別（Inner class）

• 使用內部類別的好處在於可以直接存取外部類別的私用（private）成員，舉個例子來說，在視窗程式中，您可以使用內部類別來實作一個事件傾聽者類別，這個視窗傾聽者類別可以直接存取視窗元件，而不用透過參數傳遞。
  
• 另一個好處是，當某個Slave類別完全只服務於一個Master類別時，我們可以將之設定為內部類別，如此使用Master類別的人就不用知道 Slave的存在。
  

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So what are inner classes good for anyway?

The advantages of inner classes can be divided into three categories:

• an object-oriented advantage,
• an organizational advantage, and
• a call-back advantage.