Member var and Static var.

 /*
 member variable and static variable:
 1,invoke ways:
 member variable,also called 'instance' variable,which can only be invoked by instance.
 static variable,also called 'class' variable,which [can also] invoked by class,and it is recommended that it invoked using 'class' rather than 'instance'.
 2,storage places:
 instance variable is stored in the 'heap',
 whereas, static variable is stored in the static area of the 'method area'.
 3,life cycle:
 static var exists as the existence of the class, and gone as the disappear of the class.[general] the 'class' exists when the JVM works,and disappear when the JVM stopped.
 instance var exists as the existence of the instance,and gone when the instance was released.
 4,memory location:
 static var located in the static area of the Method Area,whereas,
 instance var located in the heap.
 */
 package kju.obj;

 import static kju.print.Printer.*;
 public class InstanceVarStaticVar {
     public static void main(String[] args) {
         println(Person.country);    //use the 'static' var by 'class' instead of the instance.
         printHr();
         Person lily = new Person("lily");
         println(lily.getName());
         println("set:");
         lily.setName("lucy");
         println(lily.getName());
         println();
     }
 }

 class Person {
     public static final String  country = "cn";
     public Person(String name) {
         this.name = name;
     }

     public void setName(String name) {
         this.name = name;
     }
     public String getName() {
         return name;
     }

     private String name;
 }