Pattern（設計模式）。單例模式（Singleton）：表示一個類只會生成唯一的一個對象。

 1 package eameple; 2 public class SingletonTest 3 { 4     public static void main(String[] args) 5     { 6         Singleton singleton = Singleton.getInstance(); 7         Singleton singleton2 = Singleton.getInstance(); 8  9         System.out.PRintln(singleton == singleton2);10     }11 }12 class Singleton13 {14     private static Singleton singleton=new Singleton();15     16     private Singleton()17     {18         19     }20     public static Singleton getInstance()21     {22         return singleton;23     }24 25 26 }