What is the cause of this NullPointerException? - Java

Question

I am currently working on a project and am getting a NullPointerException and can't find the location/source of the exception. The code I have used is:

public static void AccessAccount(){
    try{
        System.out.println("Enter your card number to access your account:");
        int CardNumber = sc.nextInt();
        String CardNumberStr = Integer.toString(CardNumber);
        boolean Exist = false;
        String LineNo;
        String [] CardNum = {};
        int Counter;
        FileReader fileReader = new FileReader("VirtualATM.txt");
        BufferedReader bufferedReader = new BufferedReader(fileReader);
        line = bufferedReader.readLine();
        CardNum = line.split("\\s+");
        do{
            for(Counter = 0; Counter < CardNum.length; Counter++){
                LineNo = CardNum[Counter];
                if(LineNo.contains(CardNumberStr)){
                    Exist = true;
                }
                else if(Counter == CardNum.length){
                    Exist=false;
                }
            }
            //add this line to read another line of the file
            //and check if it exists
            line = bufferedReader.readLine();
        }while(!Exist && line != null);
        System.out.print("Enter your pin: ");
        int EnterPin = 0000;
        try{
            EnterPin = sc.nextInt();
        }catch(InputMismatchException e){
            e.printStackTrace();
            System.out.println(e.getMessage());
        }
        boolean pinTrue = false;
        String EnteredPin = Integer.toString(EnterPin);
        line = bufferedReader.readLine();
        String [] PinSearch = {};
        PinSearch = line.split("\\s+"); /**** LINE 146 IS HERE***/
        do{
            for(int search = 0; search < PinSearch.length; search++){
                String SearchForPin = PinSearch[search];
                if(SearchForPin.contains(EnteredPin)){
                    pinTrue = true;
                }
                else if(search == PinSearch.length){
                    pinTrue = false;
                }
            }
            line = bufferedReader.readLine();
        }while(pinTrue == false && line != null);
        bufferedReader.close();
    }catch(FileNotFoundException e){
        e.printStackTrace();
        System.out.println(e.getMessage());
    }catch(IOException e){
        e.printStackTrace();
        System.out.println(e.getMessage());
    }
}

The error given is as follows:

java.lang.NullPointerException
    at VirtualATM.AccessAccount(VirtualATM.java:146)
    at VirtualATM.RegisterNewCard(VirtualATM.java:95)
    at VirtualATM.main(VirtualATM.java:35)

If anyone could help me find the source of the problem, that would be great.

Line 146 looks like a good place to start. Which line is that? When you debug this, which object is `null`? Where do you expect that object to be initialized? — David, Sep 01 '14 at 16:45
Uh, the source of the problem is line 146. (Hint: Learn how to debug.) — Hot Licks, Sep 01 '14 at 16:45
Everything you need to know about a NPE is in the canonical answer. — Jeroen Vannevel, Sep 01 '14 at 16:48
Side note: you should consider consistently naming your variables in accordance with [Java naming conventions](http://www.oracle.com/technetwork/java/codeconventions-135099.html) — DeathByTensors, Sep 01 '14 at 16:49
This line `line = bufferedReader.readLine();`, which is written just before `String [] PinSearch = {};`, is returning `null`. Since there is nothing more to read from the file, that is why the `do-while` loop ended at first place. So seems like `line 144` is what is giving `null` to the `line` variable, and on line `146` you using that `null` reference, for invoking `split` — nIcE cOw, Sep 01 '14 at 16:54

score 0 · Accepted Answer · answered Sep 01 '14 at 16:46

0

Probably you are not oppenig the file, check the status of fileReader variable. and if is null, you have to check the path of your file

answered Sep 01 '14 at 16:46

Juan Camilo Mejia

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What is the cause of this NullPointerException? - Java

1 Answers1