int i1 = 1;
        int i2 = 1;
        System.out.println("i1==i2 : " + (i1 == i2)); // true
  
        Integer num1 = 1; 
        int num2 = 1;
        System.out.println("num1 == num2 : " + (num1 == num2)); // true 自動拆箱 
 
        Integer test1 = 121; 
        Integer test2 = 121; 
        System.out.println("tet1 == test2 : " + (test1 == test2)); // true  ( JVM會快取-128到127的Integer物件，不會產生新物件，直接指向快取地址)
        
        Integer obj1 = 1111; 
        Integer obj2 = 1111; 
        System.out.println("obj1 == obj2 : " + (obj1 == obj2)); // false 超過127之後就會產生新的物件
       
        Integer one = new Integer(1);
        Integer aOne = new Integer(1);
        System.out.println("one == aOne : " + (one == aOne)); // false  屬於兩個不同物件
		
        String am="test";
        String amm="test";
        System.out.println("am == amm :"+(am==amm));//true  m 和mm指向同一地址
        
        String wt=new String("tt");
        String wtt=new String("tt");
        System.out.println("wt == wtt :"+(wt==wtt));//false   t 和tt 是兩個不同物件