==号并不能判断两个引用的值，系统会报错
public class Dog {
int age=18;
}
public class Dog1 {
int age=18;
}
public class Init {
public static void main(String[] args) {
Dog o=new Dog();
Dog1 o1=new Dog1();
if(o==o1){
System.out.println("相同");
}
else{
System.out.println("不相同");
}
}
}
