实例字段与静态字段

import java.util.*;/**来 自 n o w    j a v a  . c o m**/


public class AClass {


    public int instanceInteger = 0;


    public int instanceMethod() {

        return instanceInteger;

    }


    public static int classInteger = 0;


    public static int classMethod() {

        return classInteger;

    }


    public static void main(String[] args) {

        AClass anInstance = new AClass();

        AClass anotherInstance = new AClass();


        //Refer to instance members through an instance./**from n o w j a v a . c o m**/

        anInstance.instanceInteger = 1;

        anotherInstance.instanceInteger = 2;

        System.out.format("%s%n", anInstance.instanceMethod());

        System.out.format("%s%n", anotherInstance.instanceMethod());


        //Illegal to refer directly to instance members from a class method

        //System.out.format("%s%n", instanceMethod());    //illegal

        //System.out.format("%s%n", instanceInteger);     //illegal


        //Refer to class members through the class...

        AClass.classInteger = 7;

        System.out.format("%s%n", classMethod());


        //...or through an instance.

        System.out.format("%s%n", anInstance.classMethod());


        //Instances share class variables

        anInstance.classInteger = 9;

        System.out.format("%s%n", anInstance.classMethod());

        System.out.format("%s%n", anotherInstance.classMethod());

    }

}