using hasNextLine() but still getting java.util.NoSuchElementException: No line found

Question

I'm doing a programming project and keep getting the error shown below.

Exception in thread "main" java.util.NoSuchElementException: No line found
    at java.util.Scanner.nextLine(Scanner.java:1585)
    at ArrayPhoneDirectory.loadData(ArrayPhoneDirectory.java:42)
    at ArrayPhoneDirectoryTester.main(ArrayPhoneDirectoryTester.java:18)

I thought this would be because the scanner read.nextLine() is going past the end of the text file. But I've used a while loop with hasNextLine so I'm not sure why this is happening. Anyone know where I'm going wrong?

 public void loadData (String sourceName){
Scanner read = new Scanner(sourceName);

while (read.hasNextLine()) {
    String name = read.nextLine();
    String telno = read.nextLine(); //ArrayPhoneDirectory Line 42
    add(name, telno);
  }
 }

Associated text file

John
123
Bill
23
Hello
23455
Frank
12345
Dkddd
31231

how is your data? can you please show? Is it `name` in one line and `telno` in another and so on? or what? — tod, Apr 24 '14 at 14:30
@tod My data looks exactly as you guess. Below is the short version I'm testing with. John 123 Bill 23 Hello 23455 Frank 12345 Dkddd 31231 — Sam, Apr 24 '14 at 14:32
@Sam If you have some additional informations which could be relevant to question then you should put them in your question, not just post it as comment. So try to use [[edit]] option under your question and include your additional informations there. — Pshemo, Apr 24 '14 at 14:34
@Sam can you add it into the question, it is not clear here in the comment.. — tod, Apr 24 '14 at 14:35
Data you posted do not cause problem you described. Are you sure that you don't have odd number of lines you are scanning? — Pshemo, Apr 24 '14 at 14:41
If you take a look at [this example](http://ideone.com/bZmABg) you will see no problems with your code and your data. Can we see how are you using your method? — Pshemo, Apr 24 '14 at 14:44

score 6 · Answer 1 · answered Apr 24 '14 at 14:26

6

You are reading two lines while only checking for the existence of one

Here is the second read

String telno = read.nextLine(); //ArrayPhoneDirectory Line 42

answered Apr 24 '14 at 14:26

geoand

49,266
16
140
156

Thanks, is there an easy way to fix this? – Sam Apr 24 '14 at 14:29
No problem. One solution would be to use `read.hasNextLine()` again before reading the line. Another would be to actually have both pieces of data on the same line and parsing that line into the name and telno – geoand Apr 24 '14 at 14:32

score 1 · Answer 2 · answered Apr 24 '14 at 14:27

1

hasNextLine checks for only one line. You are trying to read two lines.

String name = read.nextLine();
String telno = read.nextLine();

which in case of odd number of lines can throw NoSuchElementException for second line you want to read.

answered Apr 24 '14 at 14:27

Pshemo

113,402
22
170
242

score 0 · Accepted Answer · answered Apr 24 '14 at 14:28

hasNextLine()

will check only for one new line. you cannot read two lines after checking for just one.

If you have to continuously read records then you could do

public void loadData (String sourceName){
    Scanner read = new Scanner(sourceName);
    int i = 1;

    while (read.hasNextLine()) {
        if(i%2 != 0)
            String name = read.nextLine();
        else
            String telno = read.nextLine(); //ArrayPhoneDirectory Line 42
        add(name, telno);
        i++;
    }
}

I'm yet to get test it fully but this seems to have solved the errors I was getting, thanks :) — Sam, Apr 24 '14 at 14:41

Ankit Bansal · Answer 4 · 2014-04-24T14:39:56.147

0

Once you call nextLine the pointer gets incremented. Since, you have already called it before in this line:

String name = read.nextLine();

So, the next time you try to read it over here:

String telno = read.nextLine();

you get no such element exception. You should use this instead:

String telno = name

edited Apr 24 '14 at 14:39

answered Apr 24 '14 at 14:29

Ankit Bansal

4,521
20
39

score -1 · Answer 5 · answered Apr 24 '14 at 14:34

What you're doing is reading too many lines when checking for only one. It goes like this:

Problem

If the array on "lines" looks like this:

["This is line 1"]

Then read.hasNextLine() will return true. Then you enter your while loop. You run the first line which is:

String name = read.nextLine();

You retrieved one element from the above array, now it looks like this:

[]

Then you continue through your while loop:

String telno = read.nextLine();

Then the nextLine() method looks for a element in the array to give you, doesn't find any, and throws an exception.

using hasNextLine() but still getting java.util.NoSuchElementException: No line found

5 Answers5

Problem

Linked

Related