成员变量和局部变量 （静态变量）类变量和实例变量

public class Dog {
public static int age;
public String name;
public void study(){
this.name=name;
}
public static void main(String[] args) {
System.out.println(Dog.age);0
Dog s1=new Dog();
s1.name="齐天大圣";
s1.age=20;
System.out.println(s1.name);齐天大圣
System.out.println(s1.age);20
System.out.println(Dog.age);20
Dog s2=new Dog();
System.out.println(s2.name);null
System.out.println(s2.age);20

}
}