static关键字

public class Cat
{
    private static int sid=0;
    private String name;
    int id;
    Cat(String name)
    {
       this.name=name;
       id=sid++;
    }            
    public void info()
    {
       System.out.println(id);
    }
    public static void main(String arg[])
    {
       Cat.sid=100;
       Cat mimi=new Cat("mimi");
       Cat mimi1=new Cat("mimi");
       Cat.info();       
    }
}