新手！求帮忙看下报错代码！

package zs1;

public class zs17
{
        static int[] data={2,5,7,3,8,9,4,};
        static int index=8;
        static void insert(int pos,int value)
        {
            if (index==data.length) expand();
            for(int i=index;i>pos;i--)
            {
                data[i]=data[i-1];
            }
            data[pos]=value;
            index++;
        }
        static void delete(int pos)
        {
            index--;
            for(int i=pos;i<index;i++)
            {
                data[i]=data[i+1];
            }
        }
        static void expand()
        {
            int[] a=new int[data.length*2];
            System.arraycopy(data,0,a,0,data.length);
            data=a;
        }
        static void print()
        {
            for(int i=0;i<index;i++)
            {
                System.out.print(data[i]+"");
            }
            System.out.println();
        }
        public static void main(System[] args)
        {
            insert(2,1);
            print();
            delete(1);
            print();
        }
}