成员变量（对象共享类变量及常量的用法）Example4_4//Example4_5

class Lader{
 double above,height;
 static double bottom;
 void setAbove(double a){
  above=a;
 }
 void setBottom(double b){
  bottom=b;
 }
 double getAbove(){
  return above;
 }
 double getBottom(){
  return bottom;
 }
 
 }
 class Example4_4{
 public static void main(String arg[]){
  Lader.bottom=60;
  Lader laderOne,laderTwo;
  System.out.println("现在所有Lader对象的bottom都是:"+Lader.bottom);
  laderOne=new Lader();
  laderTwo=new Lader();
  System.out.println("laderOne的bottom:"+laderOne.getBottom());
  System.out.println("laderTwo的bottom:"+laderTwo.getBottom());
  laderOne.setAbove(11);
  laderTwo.setAbove(22);
  laderTwo.setBottom(100);
  System.out.println("现在所有Lader对象的bottom都是:"+Lader.bottom);
  System.out.println("laderOne的above:"+laderOne.getAbove());
  System.out.println("laderTwo的above:"+laderTwo.getAbove());
 }
 
 
}

如果成员变量被final修饰，就被叫做常量。（下例为常量的用法）

class Tom{
 final int MAX=100;
 static final int MIN=20;
 }
 public class Example4_5{
 public static void main(String args[]){
  System.out.println(Tom.MIN);
  Tom cat=new Tom();
  int x=0;
  x=Tom.MIN+cat.MAX;
  System.out.println(x);
 }
}