java.util.NoSuchElementException: No line found

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");
}

Solution 1:

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

Solution 2:

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

https://docs.oracle.com/javase/8/docs/api/java/util/Scanner.html

Solution 3:

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.

Solution 4:

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.