cannot determine the cause of these test errors, debugger isnt functioning here, nor can i figure out how to resolve this

the task here is to create a file, create a object called Student that takes a name, age gpa. the file is filled with lines that look roughly like this name=Jane Robinson,age=19,gpa=3.81 while reading each line I am to split the "," and the "=" and then check each index of array for "name", "age", "gpa" if one of those are found, to then substring(startpostion, rest of string); and save that as a variable, call the Student setters for each variable and set them, then load the newly set up Student objects into a ArrayList called result, that I may then return it.

import java.util.ArrayList;
import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;
/**
* 
*
*
*
*/
public class StudentReader {
public static Student[] readFromTextFile(String fileName) {
ArrayList<Student> result = new ArrayList<Student>();
String name =" ";
int age = 0;
double gpa = 0.0;
String fill;
File f = new File(fileName);
Scanner n = null;
try
{
n = new Scanner(f);
}
catch(FileNotFoundException ex)
{
ex.printStackTrace();
}
while (n.hasNextLine())
{
fill = n.nextLine();
Student g =  new Student(name , age, gpa);
String[] string1 = fill.split(",");
String[] string2;
for (int i = 0; i < string1.length; ++i)
{
string2 = string1[i].split("=");
if (string2[i].substring(0,4).equals("name"))
{
name = string2[i].substring(4,string2[i].length());
}
if(string2[i].substring(0,3).equals("age"))
{
age = Integer.parseInt(string2[i].substring(3,string2[i].length()));
}
if(string2[i].substring(0,3).equals("gpa"))
{
gpa = Double.parseDouble(string2[i].substring(3,string2[i].length()));
}
}
} 
return result.toArray(new Student[0]);
}
}

errors here:

ERROR IN YOUR CODE - testRead10Lines(StudentReaderTest):
begin 0, end 4, length 2
java.lang.StringIndexOutOfBoundsException
at java.base/java.lang.String.checkBoundsBeginEnd(String.java:3116)
at java.base/java.lang.String.substring(String.java:1885)
at StudentReader.readFromTextFile(StudentReader.java:43)
at StudentReaderTest.testRead10Lines(StudentReaderTest.java:104)
2. ERROR IN YOUR CODE - testReadSingleLine(StudentReaderTest):
begin 0, end 4, length 2
java.lang.StringIndexOutOfBoundsException
at java.base/java.lang.String.checkBoundsBeginEnd(String.java:3116)
at java.base/java.lang.String.substring(String.java:1885)
at StudentReader.readFromTextFile(StudentReader.java:43)
at StudentReaderTest.testReadSingleLine(StudentReaderTest.java:84)
3. ERROR IN YOUR CODE - testFileNotExist(StudentReaderTest):
java.lang.NullPointerException
at StudentReader.readFromTextFile(StudentReader.java:32)
at StudentReaderTest.testFileNotExist(StudentReaderTest.java:113)

like I said in the question for some reason my debugger wont show me the cause here and I cant identify why the length of each object is only 2, I don't have any other information to give here as I have the whole task listed in the top. but can anyone tell me why I'm running these index out of bounds errors

It's the substring that's causing the issue.

It should be:

  if (string2[i].substring(0,3).equals("name"))
{
name = string2[i].substring(3,string2[i].length());
}
if(string2[i].substring(0,2).equals("age"))
{
age = Integer.parseInt(string2[i].substring(2,string2[i].length()));
}
if(string2[i].substring(0,2).equals("gpa"))
{
gpa = Double.parseDouble(string2[i].substring(2,string2[i].length()));
}