public class Test {
static ArrayList list = null;
static void read(ArrayList list) {
if(list == null) {
list = new ArrayList();
}
//String s =new String("hello");
list.add("hello");
System.out.println(list.size());
}
public static void main(String[] args) {
read(list);
System.out.println(list.size());
}
}
很简单的代码,为什么会抛异常呢?