一个类的static变量在其所有实例化对象上是共享的

public class Test {
public static void main(String args[]){
staticValue a=new staticValue();
staticValue b=new staticValue();
a.add();
b.printA();
}
}
class staticValue {
static int a=1;
public void add(){
a++;
}
public void printA(){
System.out.println(a);
}
}