三道容易错的面试题

试题一:

               int a1= 10;

               Integer a2 =new  Integer(10);

System.out.println(a1==a2);

int a = 2;
switch(a){
case 1:
System.out.println("1");
case 2:
System.out.println("2");
case 3:
System.out.println("3");

}

                double total  =1;
float  param1 =0.1f;
double param2 =0.1;
System.out.println(total-param1);
System.out.println(total-param2);结果：

true

2

3

0.8999999985098839
0.9