单例模式初步

public class Single {    //构造方法私有化     private Single(){     }     //由于方法是静态的 所以s也要是静态变量   只赋一次初值   私不私有都可以     static Single s=null;     public static Single getInstance()     {           if(s==null)        s=new Single();         return s;     }}

public class Test {

public static void main(String[] args) {    // TODO Auto-generated method stub           Single s1 = Single.getInstance();           Single s2 = Single.getInstance();           System.out.println(s1==s2);}

}