Thread: Programme producing NullPointerException

Am new to programming and am trying to create a system that is similar to a train timetable system.
I want the user to be able to enter the stops between two stations ( from a preset list of 5 stations ) and this be saved as an array list, and this array list be saved accordingly within a 2D array so if they were to look in [1][2] there would be an arraylist of stops between station 1 and 2.

I used this to initialise the array of arraylists (in a class i created called stops)

ArrayList<String>[][] stopsArray= (ArrayList<String>[][])new ArrayList[5][5];
 
	public void stops(){
		for (int i = 0; i<5; i++){
			for (int j=0; j<5; j++){
				stopsArray[i][j]= new ArrayList<String>();
			}
		}
	}

Then I use this code to set the stops

 
	public void setNoStops(int stopsNo){
		noOfStops = stopsNo;
	}
 
	public void setStops(int start, int end ){
		for (int i=0; i< noOfStops ; i++){
			System.out.println("Print Stop Number"+(i+1)+" :");
			stopsArray[start][end].add(scanner.nextLine());
		}
	}

The bottom written line of code is mentioned in the null pointer error I recieve

Then in my main programme I declare the new object and use these methods
the method options displays the list of five stations with a number reference

 
System.out.println("Please choose a start station :");
						options();
						place1 = scanner.nextInt();
						System.out.println();
 
						System.out.println("Please choose an end station :");
						options();
						place2 = scanner.nextInt();
						System.out.println();
 
						System.out.println("Enter number of stops");
						stopsno = scanner.nextInt();	
						mystops.setNoStops(stopsno);
						mystops.setStops(place1-1,place2-1);

mystops is the object I created to store the information.

when compiling I recieve no errors
when I run the program it runs smoothly, asks for the number of stops, allows the user to enter a number, then says enter stop 1, I enter a word and the program crashes giving the error java.lang.NullPointerException

can someone please explain where my program is going wrong?
thanks!

Exception in thread "main" java.lang.NullPointerException
at myCourseworkPackage.stops.setStops(stops.java:26)
at train.main(train.java:179)

Thats the full error message
line 26 of stops is the

stopsArray[start][end].add(scanner.nextLine());

and line 179 of main is

mystops.setStops(place1-1,place2-1);

as seen in the code of my original post

I have printed the array out because what I am trying to do is have the user input an arraylist into various array values. For example for [1][3]'s value I would try add the places "derby" and "nottingham" as an arraylist?

I used the code you gave me and it is saying all the values are null which I am guessing is the problem?
I want the users input to change the value from null to the input?
Could you explain why my code isn't doing that?

Thank you for helping out, I'm new at this and finding it hard to get my head around