java.util.NoSuchElementException: No line found

Question

I got an run time exception in my program while I am reading a file through a Scanner.

java.util.NoSuchElementException: No line found     
   at java.util.Scanner.nextLine(Unknown Source)    
   at Day1.ReadFile.read(ReadFile.java:49)  
   at Day1.ParseTree.main(ParseTree.java:17)

My code is:

while((str=sc.nextLine())!=null){
    i=0;
    if(str.equals("Locations"))
    {
        size=4;
        t=3;
        str=sc.nextLine();
        str=sc.nextLine();
    }
    if(str.equals("Professions"))
    {
        size=3;
        t=2;
        str=sc.nextLine();
        str=sc.nextLine();
    }
    if(str.equals("Individuals"))
    {
        size=4;
        t=4;
        str=sc.nextLine();
        str=sc.nextLine();
    }

int j=0;
String loc[]=new String[size];
while(j<size){
    beg=0;
    end=str.indexOf(',');
    if(end!=-1){
        tmp=str.substring(beg, end);
        beg=end+2;
    }
    if(end==-1)
    {
        tmp=str.substring(beg);
    }
    if(beg<str.length())
        str=str.substring(beg);
    loc[i]=tmp;
    i++;

    if(i==size ){
        if(t==3)
        {
            location.add(loc);
        }
        if(t==2)
        {
            profession.add(loc);
        }
        if(t==4)
        {
            individual.add(loc);
        }
        i=0;
    }
    j++;
    System.out.print("\n");
}

Welcome to SO. When posting code you should take care to format it for readability... i.e. remove unnecessary blank lines, indent properly. Also format your stacktrace as code to make it readable. I fixed the formatting for you. — Jim Garrison, Aug 26 '11 at 18:44
Also, you left out the most important piece, which is how `sc` was declared and opened. — Jim Garrison, Aug 26 '11 at 18:45

ratchet freak · Accepted Answer · 2018-01-31T16:52:38.647

42

with Scanner you need to check if there is a next line with hasNextLine()

so the loop becomes

while(sc.hasNextLine()){
    str=sc.nextLine();
    //...
}

it's readers that return null on EOF

ofcourse in this piece of code this is dependent on whether the input is properly formatted

edited Jan 31 '18 at 16:52

answered Aug 26 '11 at 19:13

ratchet freak

44,814
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score 15 · Answer 2 · answered Aug 26 '11 at 18:44

15

You're calling nextLine() and it's throwing an exception when there's no line, exactly as the javadoc describes. It will never return null

http://download.oracle.com/javase/1,5.0/docs/api/java/util/Scanner.html

answered Aug 26 '11 at 18:44

Brian Roach

72,790
10
128
154

score 10 · Answer 3 · answered Dec 06 '18 at 19:07

I also encounter with that problem. In my case the problem was that i closed the scanner inside one of the funcs..

public class Main 
{
 public static void main(String[] args) 
 {
  Scanner menu = new Scanner(System.in);
        boolean exit = new Boolean(false);
    while(!exit){
  String choose = menu.nextLine();
        Part1 t=new Part1()
        t.start();
     System.out.println("Noooooo Come back!!!"+choose);
  }
 menu.close();
 }
}

public class Part1 extends Thread 
{
public void run()
  { 
     Scanner s = new Scanner(System.in);
     String st = s.nextLine();
     System.out.print("bllaaaaaaa\n"+st);
     s.close();
 }
}

The code above made the same exaption, the solution was to close the scanner only once at the main.

I have the similar problem. I want to know why it wont work if I close the scanner and re-initialise it again when I read next line. They should both be different instances of scanner right? Why would closing one instance of scanner affect the other one? — Kaushik Evani, Nov 13 '19 at 16:39

William Hou · Answer 4 · 2020-07-24T20:24:20.910

Your real problem is that you are calling "sc.nextLine()" MORE TIMES than the number of lines.

For example, if you have only TEN input lines, then you can ONLY call "sc.nextLine()" TEN times.

Every time you call "sc.nextLine()", one input line will be consumed. If you call "sc.nextLine()" MORE TIMES than the number of lines, you will have an exception called

      "java.util.NoSuchElementException: No line found".

If you have to call "sc.nextLine()" n times, then you have to have at least n lines.

Try to change your code to match the number of times you call "sc.nextLine()" with the number of lines, and I guarantee that your problem will be solved.

score 7 · Answer 5 · answered Feb 03 '16 at 09:50

For whatever reason, the Scanner class also issues this same exception if it encounters special characters it cannot read. Beyond using the hasNextLine() method before each call to nextLine(), make sure the correct encoding is passed to the Scanner constructor, e.g.:

Scanner scanner = new Scanner(new FileInputStream(filePath), "UTF-8");

score 0 · Answer 6 · answered Sep 11 '19 at 14:59

Need to use top comment but also pay attention to nextLine(). To eliminate this error only call

sc.nextLine()

Once from inside your while loop

 while (sc.hasNextLine()) {sc.nextLine()...}

You are using while to look ahead only 1 line. Then using sc.nextLine() to read 2 lines ahead of the single line you asked the while loop to look ahead.

Also change the multiple IF statements to IF, ELSE to avoid reading more than one line also.

java.util.NoSuchElementException: No line found

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