Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 4 이렇게 오류가 나는게 왜 나는지 잘 모르겠습니다.

package Baseball;
import java.util.Scanner;
import java.io.*;

public class Pl_Modify
{
public static void clearScreen()
{
for (int i = 0; i < 80; i++)
System.out.println(" ");
}

private String[] arr;

public void pl_modify()
{
Scanner scan = new Scanner(System.in);
LoginCtr logctr = new LoginCtr();
PlayerList playerlist = new PlayerList();
int choice;
String result = "";
String group = "";
String name = "";
playerlist.playerlist();
System.out.println(" ");
System.out.print("수정할 선수를 입력하세요 : ");
name = scan.nextLine();
System.out.println("");
System.out.println("1. 구단");
System.out.println("2. 포지션");
System.out.println("3. 비밀번호");
System.out.print("수정할 것을 고르세요 : ");
choice = scan.nextInt();

if(choice == 1)
{
try
{
BufferedReader br = new BufferedReader(new FileReader(new File("D:\\\\Java Program\\\\Baseball\\\\src\\\\Baseball\\\\player.txt")));
BufferedWriter bw = new BufferedWriter(new FileWriter(new File("D:\\\\Java Program\\\\Baseball\\\\src\\\\Baseball\\\\player.txt"), true));
PrintWriter pw = new PrintWriter(bw, true);
String row = null;
System.out.print("수정할 구단을 입력하세요 : ");
group = scan.nextLine();
while((row = br.readLine()) != null)
{
String[] arr = row.split(",");
result = arr[1].replaceFirst(arr[1], group);
if(name.equals(arr[0]))
{
pw.write(arr[0] + "," + result + "," + arr[2] + "," + arr[3] + "," + arr[4] + " ");
pw.println(" ");
pw.flush();
System.out.println("수정되었습니다.");
logctr.log_ctr();
}
}
bw.close();
br.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}

이런식으로 입력받은 구단을 수정하려고 하는데 이름입력과 구단입력에서
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 4
이러한 오류가 납니다.

왜 이렇게 나오는 것일까요 ,...ㅜㅜ

그리고 가능하다면 수정한것을 텍스트에 덮어쓰고싶은데 다음줄로 저장이 됩니다. 어떻게 하는지 알려주세요ㅜㅜ