New drivers licence question from code coach

Question

Can i please know why am i getting an array out of bound exception here :
import java.util.*;
public class Program
{
public static void main(String[] args) {
Scanner ip = new Scanner(System.in);
String n=ip.nextLine();
int a=ip.nextInt();
String on=ip.nextLine();
String [] ons=new String[5];
ons=on.split(" ");
ons[4]=n;
for(int i=0;i<5;i++)
{
for(int j=i+1;j<5;j++)
{
String temp;
if(ons[i].compareTo(ons[j])>0)
{
temp=ons[i];
ons[i]=ons[j];
ons[j]=temp;
}
}
}
for(int i=0;i<5;i++)
{
if(ons[i].equals(n))
System.out.print(((i+1)*20)/a);
}
}
}

Answer 1

You are overwriting String[] ons with split. If i enter two words, then that means the array size is going to 2 which causes error on line 11. It because you want to overwrite the fifth element, but array has only two.

Answer 2

ip.nextInt() reads integer but not delimiter after, so do one ip.nextLine() after to read the delimiter
int a = ip.nextInt();
ip.nextLine();

then you are trying add name at the end of array ons. if input has 4 names, array after split has length=4 with last index 3 and index 4 does not exist

you can and name at the end of input string (with delimiter) before spliting