import java.util.ArrayList;import java.util.List;public class A{    private int[] arr=new int[3];    private List
    
      ls;        public A(){        ls=new ArrayList
     
      ();        ls.add("12");    }        public int getArrValue(int i){        return arr[i];    }        public String getListValue(int i){        return ls.get(i);    }        public static void main(String[] args){        try{            A a=new A();            int v1=a.getArrValue(0);            String v2=a.getListValue(0);                        throw new Exception("自定义异常发生");        }catch(java.lang.NullPointerException e){            System.out.println("a未实例化或A.ls未实例化");        }catch(java.lang.IndexOutOfBoundsException e){            System.out.println("A.arr取值下标越界或A.ls取值下标越界");        }catch(Exception e){            e.printStackTrace();        }    }}