class Student {
        private String name;
        private int age;
        private static String country;
        public Student(){}
        public Student(String name, int age, String country) {
                this.name = name;
                this.age = age;
                this.country = country;
        }
        public Student(String name, int age) {
                this.name = name;
                this.age = age;
        }
        public void show() {
                System.out.println(name + "****" + age + "****" + country);
        }
}
class StaticDemo {
        public static void main(String[] args) {
                Student s1 = new Student("Lockwood", 20, "US");
                Student s2 = new Student("Lewis", 30);
                Student s3 = new Student("FishHeadJone", 50);
                s1.show();
                s2.show();
                s3.show();
        }
}

s2，s3会自动输出country的值 为US。这是因为static 修饰成员变量以后，静态成员变量会在对象之前加载进来，并且，静态的成员变量可以实现数据的共享。

看看楼主的，static修饰符的作用

static这块总是搞混

static 也起到复用的效果了