ava私人建设者的目的

public class Tester {

   private static Tester instance;

   private Tester(){}



   public static Tester getInstance(){

      if(instance == null){

         instance = new Tester();

      }

      return instance;

   }



   public static void main(String[] args) {

      Tester tester = Tester.getInstance();

      Tester tester1 = Tester.getInstance();

      System.out.println(tester.equals(tester1));

   }   

}