Help with java.util.NoSuchElementException

[S. Eckstrom]

Hello, I am working on code for a class. I am a beginner and need some help. The assignment is 7 parts long and I keep getting an error right away. I'm thinking it is a simple fix, but I can't figure it out.
I've been doing research and am wondering about adding "hasNextLine()", but I don't know where. Thank you for you help.
Here is the error:

Enter a sample text:Exception in thread "main" java.util.NoSuchElementException: No line found
                                                                                                                      at java.base/java.util.Scanner.nextLine(Scanner.java:1651)
                                                                                                                      at AuthoringAssistant.inputString(AuthoringAssistant.java:44)
                                                                                                                      at AuthoringAssistant.main(AuthoringAssistant.java:8)

Here is my code: ( I hope I am doing this correctly, as last time I was told I did not.)

import java.util.Scanner;

public class AuthoringAssistant {
   private static Scanner scnr2;
   private static Scanner scnr3;
   public static void main(String[] args) {
      /* Type your code here. */
       String mainString = inputString();
    char menuChoice = '?';
    while(menuChoice != 'q'){
      menuChoice = printMenu();
      if(menuChoice == 'c'){
      }
      else if(menuChoice == 'w'){
      }
      else if(menuChoice == 'f'){
        System.out.print("Enter the word or phrase to be found : ");
      }
      else if(menuChoice == 'r'){
      	String output = replaceExclamation(mainString);
      	System.out.println("Edited string is :\n"+output);
      }
      else if(menuChoice == 's'){
      	String output = shortenSpace(mainString);
      	System.out.println("Edited string is :\n"+output);
      }
      else if(menuChoice == 'q'){
      	System.out.println("Goodbye!!!");
      }
      else{
        System.out.println("You entered a wrong option.Please select the correct option again!!!");
      }
    }
  }
    
  public static String inputString(){
     /*
     1. Prompt the user to enter a string of their choosing.
         Store the text in a string.  Output the string. */
  scnr2 = new Scanner(System.in);
    String mainString = "";
    
    System.out.println("Enter a sample text:");
    mainString = scnr2.nextLine();
    
    System.out.println("You entered: ");
    System.out.println(mainString);
    
    return mainString;
  }
  
  public static char printMenu(){
      /* 
      2.Implement a printMenu() method, which outputs a menu of user options for analyzing/editing the string, 
         and returns the user's entered menu option. Each option is represented by a single character.
      If an invalid character is entered, continue to prompt for a valid choice. Hint: Implement Quit before 
         implementing other options. Call printMenu() in the main() method. 
         Continue to call printMenu() until the user enters q to Quit. */
  scnr3 = new Scanner(System.in);
    char menuChoice;
    System.out.println("MENU");
    System.out.println("c - Number of non-whitespace characters");
    System.out.println("w - Number of words");
    System.out.println("f - Find text");
    System.out.println("r - Replace all !'s");
    System.out.println("s - Shorten spaces");
    System.out.println("q - Quit");
    System.out.print("Enter your choice : ");
    menuChoice = scnr3.next().charAt(0);
    return menuChoice;
  }
  public static int getNumOfNonWSCharacters(String mainString){
		/*
		3.Implement the getNumOfNonWSCharacters() method. getNumOfNonWSCharacters() has a string 
		  as a parameter and returns the number of characters in the string, excluding all whitespace. 
		  Call getNumOfNonWSCharacters() in the main() method */
		char characters[] = mainString.toCharArray();
    int numOfNonWSChars = 0;
		for(int i=0;i<mainString.length();i++){
		  if(characters[i]==' '){
		    continue;
		  }
		  else{
		    numOfNonWSChars++;
		  }
		}
		System.out.println("The number of non-whitespace characters in the string : " + numOfNonWSChars);
	  return numOfNonWSChars;
	}
	public static int getNumOfWords(String mainString){
	  /*
     4.Implement the getNumOfWords() method. getNumOfWords() has a string as a parameter and returns the 
       number of words in the string. Hint: Words end when a space is reached except for the last word in a sentence.
       Call getNumOfWords() in the main() method */
	  char characters[] = mainString.toCharArray();
    int numOfWords = 0;
    boolean flag = true;
		for(int i=0;i<mainString.length();i++){
		  if(flag==true&&characters[i]!=' '){
		    flag = false;
		    numOfWords++;
		    continue;
		  }
		  else{
		    if(characters[i]==' '&&flag==false){
		      flag = true;
		    }
		    else{
		      continue;
		    }
		  }
		}
		System.out.println("The number of words in the string : " + numOfWords);
	  return numOfWords;
	}
	public static int findText(String mainString,String findText){
		/*
		5.Implement the findText() method, which has two strings as parameters. The first parameter is the text
		   to be found in the user provided sample text, and the second parameter is the user provided sample text. 
		   The method returns the number of instances a word or phrase is found in the string. 
		   In the main() method, prompt the user for a word or phrase to be found and then call findText() in the main() method. */
		int count  = mainString.replaceAll("[^" + findText + "]", "").length() / findText.length();
		if(count>0){
		  System.out.println(findText+" occurs "+count+" times in "+mainString);
		}
		else{
		  System.out.println(findText+" didn't occur in "+mainString);
		}
	  return count;
	}
	public static String replaceExclamation(String mainString) {
		/*
      6.Implement the replaceExclamation() method. replaceExclamation() has a string parameter and returns a 
		   string which replaces each '!' character in the string with a '.' character. 
		   replaceExclamation() DOES NOT output the string. Call replaceExclamation() in the main() method, 
		   and then output the edited string. */
		String output = "";
		char characters[] = mainString.toCharArray();
		for(int i=0;i<mainString.length();i++){
		  if(characters[i]=='!'){
		    output = output + '.';
		  }
		  else{
		    output = output + characters[i];
		  }
		}
		return output;
	}
	public static String shortenSpace(String mainString){
	   /* 
	   7.Implement the shortenSpace() method. shortenSpace() has a string parameter and returns a 
	      string that replaces all sequences of 2 or more spaces with a single space. 
	      shortenSpace() DOES NOT output the string. Call shortenSpace() in the main() method, and then 
	      output the edited string.*/
	  String output = mainString.replaceAll("\\s{2,}", " ");
		return output;
   }
}

[Campbell Ritchie]

Yes, those code tags look correct. Your indentation is however inconsistent; I think there isn't enough indentation before lines 9 and 11, for example.
Where are you suffering the exception? Is it line 44 in what you posted? I can't see how yo ucan get an exception there. Not unless you have closed System.in.
Why have you got several Scanners reading System.in? You only need one.

Please tell us the exact input you are using to get such an exception, including any control characters, e.g. ctrl‑D/ctrl‑Z.

[Liutauras Vilda]

I don't get such error running your code.

One tip: look for the simpler way to implement your current replaceExclamation(String) method. Check String's documentation and see if you could find something useful there. Please report back what you found.

[S. Eckstrom]

I didn't get any with Eclipse either, but I'm new to all this Java stuff, so I may not be using Eclipse correctly. I am using 2 Scanners, how can I modify this to use just 1?

[Carey Brown]

Make your Scanner a constant using 'final' plus the initializer. Now any member method can use SCNR.

import java.util.Scanner;
 
public class AuthoringAssistant {
   private static final Scanner SCNR = new Scanner( System.in );

   public static void main(String[] args) {
      /* Type your code here. */
       String mainString = inputString();

[S. Eckstrom]

Thank you for the reply's. This will seem dumb to you guys but if I use the " private static final Scanner SCNR = new Scanner( System.in ); " how do I re-label my scnr's I had previously? (scnr2 and scnr3).
Also will this help me with the String errors I listed at the top of the forum?

[Carey Brown]

Get rid of all other places where you create a new Scanner. Rename all your old Scanner variables  (scnr2 and scnr3) to be the new constant SCNR.

Note: The Java naming conventions say that constant name should be entirely in upper case, hence "SCNR". (I usually name mine "KEYBOARD", but, whatever.)

[Carey Brown]

This may or may not fix your program issues. When you open up more than one Scanner to System.in it becomes unpredictable.

[S. Eckstrom]

Thank you for you suggestions. I have tried the scanner changes, but the ZyBooks can't seem to get past the "Scanner.nextLine" and String issue(lines 49 & 9, bottom of post under Development errors). I can re-post the code if needed, but the scnr is really all that has changed.

This is the result I get from submitting for grading (we can submit as many times as we need until due date/time). Please notice the errors included as output under the "MENU". It is different errors than the ones I get in development mode. I'll post that below. I hope this helps. I am lost on this.

2: Compare output

Output differs. See highlights below.

Input

We'll continue our quest in space.  There will be more shuttle flights and more shuttle crews and,  yes,  more volunteers, more civilians,  more teachers in space.  Nothing ends here;  our hopes and our journeys continue!


YOUR OUTPUT

Enter a sample text:You entered: We'll continue our quest in space.  There will be more shuttle flights and more shuttle crews and,  yes,  more volunteers, more civilians,  more teachers in space.  Nothing ends here;  our hopes and our journeys continue!

Enter your choice : Exception in thread "main" java.util.NoSuchElementException
at java.base/java.util.Scanner.throwFor(Scanner.java:937)
at java.base/java.util.Scanner.next(Scanner.java:1478)
at AuthoringAssistant.printMenu(AuthoringAssistant.java:74)
at AuthoringAssistant.main(AuthoringAssistant.java:12)


EXPECTED OUTPUT

Enter a sample text:

You entered: We'll continue our quest in space.  There will be more shuttle flights and more shuttle crews and,  yes,  more volunteers, more civilians,  more teachers in space.  Nothing ends here;  our hopes and our journeys continue!

Choose an option:


Here is the errors in Develop mode:

Enter a sample text:Exception in thread "main" java.util.NoSuchElementException: No line found
    at java.base/java.util.Scanner.nextLine(Scanner.java:1651)
    at AuthoringAssistant.inputString(AuthoringAssistant.java:49)
    at AuthoringAssistant.main(AuthoringAssistant.java:9)

[Carey Brown]

This is my run of your code with SCNR fix:

Enter a sample text:
We'll continue our quest in space.  There will be more shuttle flights and more shuttle crews and,  yes,  more volunteers, more civilians,  more teachers in space.  Nothing ends here;  our hopes and our journeys continue!
You entered:
We'll continue our quest in space.  There will be more shuttle flights and more shuttle crews and,  yes,  more volunteers, more civilians,  more teachers in space.  Nothing ends here;  our hopes and our journeys continue!
MENU
c - Number of non-whitespace characters
w - Number of words
f - Find text
r - Replace all !'s
s - Shorten spaces
q - Quit
Enter your choice :

[Carey Brown]

One fix I would make is to change next() to nextLine() here

    menuChoice = SCNR.next().charAt(0);

[S. Eckstrom]

Thank you for all your time Carey Brown. I have applied the changes, but obviously I have not done it correctly. Here is my code. I am assuming that the Scanner is not applied correctly. I'm about to give up. I work 60 hrs/week and this is due tomorrow. So no much time left. Thank you anyway for all your time and help.

import java.util.Scanner;

public class AuthoringAssistant {
   private static final Scanner SCNR = new Scanner(System.in);
   
   public static void main(String[] args) {
      /* Type your code here. */
    final Scanner SCNR = new Scanner(System.in);
    String mainString = inputString();
    char menuChoice = '?';
    while(menuChoice != 'q'){
      menuChoice = printMenu();
      if(menuChoice == 'c'){
      	int n = getNumOfNonWSCharacters(mainString);
      }
      else if(menuChoice == 'w'){
      	int n = getNumOfWords(mainString);
      }
      else if(menuChoice == 'f'){
        System.out.print("Enter the word or phrase to be found: ");
        String findText = SCNR.next();
      	int n = findText(mainString,findText);
      }
      else if(menuChoice == 'r'){
      	String output = replaceExclamation(mainString);
      	System.out.println("Edited string is :\n"+output);
      }
      else if(menuChoice == 's'){
      	String output = shortenSpace(mainString);
      	System.out.println("Edited string is :\n"+output);
      }
      else if(menuChoice == 'q'){
      	System.out.println("Goodbye!!!");
      }
      else{
        System.out.println("You entered a wrong option.Please select the correct option again!!!");
      }
    }
  }
    
  public static String inputString(){
     /*
     1. Prompt the user to enter a string of their choosing.
         Store the text in a string.  Output the string. */
    final Scanner SCNR = new Scanner(System.in);
    String mainString = "";
    
    System.out.print("Enter a sample text:");
    mainString = SCNR.nextLine();
    
    System.out.print("You entered: ");
    System.out.println(mainString);
    
    return mainString;
  }
  
  public static char printMenu(){
      /* 
      2.Implement a printMenu() method, which outputs a menu of user options for analyzing/editing the string, 
         and returns the user's entered menu option. Each option is represented by a single character.
      If an invalid character is entered, continue to prompt for a valid choice. Hint: Implement Quit before 
         implementing other options. Call printMenu() in the main() method. 
         Continue to call printMenu() until the user enters q to Quit. */
    final Scanner SCNR = new Scanner(System.in);
    char menuChoice;
    System.out.println("MENU");
    System.out.println("c - Number of non-whitespace characters");
    System.out.println("w - Number of words");
    System.out.println("f - Find text");
    System.out.println("r - Replace all !'s");
    System.out.println("s - Shorten spaces");
    System.out.println("q - Quit");
    System.out.print("Enter your choice : ");
    menuChoice = SCNR.nextLine().charAt(0);
    return menuChoice;
  }
  public static int getNumOfNonWSCharacters(String mainString){
		/*
		3.Implement the getNumOfNonWSCharacters() method. getNumOfNonWSCharacters() has a string 
		  as a parameter and returns the number of characters in the string, excluding all whitespace. 
		  Call getNumOfNonWSCharacters() in the main() method */
		char characters[] = mainString.toCharArray();
    int numOfNonWSChars = 0;
		for(int i=0;i<mainString.length();i++){
		  if(characters[i]==' '){
		    continue;
		  }
		  else{
		    numOfNonWSChars++;
		  }
		}
		System.out.println("The number of non-whitespace characters in the string: " + numOfNonWSChars);
	  return numOfNonWSChars;
	}
	public static int getNumOfWords(String mainString){
	  /*
     4.Implement the getNumOfWords() method. getNumOfWords() has a string as a parameter and returns the 
       number of words in the string. Hint: Words end when a space is reached except for the last word in a sentence.
       Call getNumOfWords() in the main() method */
	  char characters[] = mainString.toCharArray();
    int numOfWords = 0;
    boolean flag = true;
		for(int i=0;i<mainString.length();i++){
		  if(flag==true&&characters[i]!=' '){
		    flag = false;
		    numOfWords++;
		    continue;
		  }
		  else{
		    if(characters[i]==' '&&flag==false){
		      flag = true;
		    }
		    else{
		      continue;
		    }
		  }
		}
		System.out.println("The number of words in the string: " + numOfWords);
	  return numOfWords;
	}
	public static int findText(String mainString,String findText){
		/*
		5.Implement the findText() method, which has two strings as parameters. The first parameter is the text
		   to be found in the user provided sample text, and the second parameter is the user provided sample text. 
		   The method returns the number of instances a word or phrase is found in the string. 
		   In the main() method, prompt the user for a word or phrase to be found and then call findText() in the main() method. */
		int count  = mainString.replaceAll("[^" + findText + "]", "").length() / findText.length();
		if(count>0){
		  System.out.println(findText+" occurs "+count+" times in "+mainString);
		}
		else{
		  System.out.println(findText+" didn't occur in "+mainString);
		}
	  return count;
	}
	public static String replaceExclamation(String mainString){
		/*
      6.Implement the replaceExclamation() method. replaceExclamation() has a string parameter and returns a 
		   string which replaces each '!' character in the string with a '.' character. 
		   replaceExclamation() DOES NOT output the string. Call replaceExclamation() in the main() method, 
		   and then output the edited string. */
		String output = "";
		char characters[] = mainString.toCharArray();
		for(int i=0;i<mainString.length();i++){
		  if(characters[i]=='!'){
		    output = output + '.';
		  }
		  else{
		    output = output + characters[i];
		  }
		}
		return output;
	}
	public static String shortenSpace(String mainString){
	   /* 
	   7.Implement the shortenSpace() method. shortenSpace() has a string parameter and returns a 
	      string that replaces all sequences of 2 or more spaces with a single space. 
	      shortenSpace() DOES NOT output the string. Call shortenSpace() in the main() method, and then 
	      output the edited string.*/
	  String output = mainString.replaceAll("\\s{2,}", " ");
		return output;
   }
}

[Carey Brown]

Delete lines 8 & 45 & 64.

Remember, only create ONE Scanner.

[S. Eckstrom]

Thank you Carey Brown. I deleted the SCNR lines as you said. but I still get the same errors on lines 9 and 49. This maybe something more stringent with ZyBooks than with an IDE. I'm not sure. I do know that all I get is this error in development and receive 9 points out of 20 for the assignment. I got a class @ 1:00pm then work @ 4:00. So I'll try until I go. Thank you for all your help. S. Eckstrom

Enter a sample text:Exception in thread "main" java.util.NoSuchElementException: No line found
   at java.base/java.util.Scanner.nextLine(Scanner.java:1651)
   at AuthoringAssistant.inputString(AuthoringAssistant.java:49)
   at AuthoringAssistant.main(AuthoringAssistant.java:9)

[Campbell Ritchie]

So what have you closed? System.in always implicitly has a next line unless you close something.

[S. Eckstrom]

I haven't closed anything that I'm aware of. It appears to be a formatting issue, causing a lack of spacing between lines. Although is highlights the lettering to like I'm missing spacing there too, but I am not.

[S. Eckstrom]

On lines 13, 16, & 21, Eclipse is giving me the following: quick fixable warning: The value of the local variable n is not used, I have changed the variable "n" to "i" as that is what is used. I still get the string errors.

[Louis Müller]

Is your assignment grading based on test cases?
To me it looks like your Scanner cant find a Line where you are telling him to find one. This may be because you have already reached the end of the input. But this seems unlikely since this is the very first action you are performing.
I think you could avoid the NoSuchElementException by adding

if(SCNR.hasNextLine()){
mainString = SCNR.nextLine();
}

This way your scanner will only go and try to read the line if there actually is a line to read.
This is a bit confusing since I cant tell what your task is. Would you care to share the assignment text?
Dont give up, even if its too late. Do it for the lesson, not for the points!

Greets, a fellow greenhorn!
Louis

[Campbell Ritchie]

Forget about what Eclipse says about variables not used. Sort out one problem at a time.
Please confirm that the exception is occurring in the inputString() method. I still think you have closed something. I am afraid that the test with if (scnr.hasNextLine()) ... might not cure your problem. It might simply push the problem elsewhere and you will get different exceptions. Please tell us exactly what input you are giving to produce that exception, including control characters.

Why have you got so many things marked static?

Don't use == true and == false
Both are bad style and error‑prone; if you write = you can get multiple errors for the price of one.
Never if (b == true) ...
Always if (b) ...
Never if (b == false) ...
Always if (!b) ...

[S. Eckstrom]

Thank you all for the help and suggestions, unfortunately, I ran out of time. I work full time 60 hrs/week in the evenings. The only time I have to do my homework is on the weekends and a few hours Monday before I leave for work. I could not figure out the problem(s) before the assignment was due Tuesday. I only received credit for 9 out of 20 points on the auto grader, which resulted in a cruddy % points. I have no time to go back over any work, as the next assignments are due weekly and I have 2 other classes as well. Again THANK YOU ALL!, Steve

[Campbell Ritchie]

S. Eckstrom wrote:. . . THANK YOU ALL! . . .

At least I can say, “That's a pleasure,” about that part of the post. Please consider whether you have bitten off more than you can chew and whether you should reduce your workload by taking longer over your course.

[Junilu Lacar]

The charAt(0) call seems to be what was causing the issue. If there was a blank line read in from the input somehow, you'll have no characters at all in the string, hence a no such character exception results.

[S. Eckstrom]

How would I fix this? I am getting a similar issue with another project.  Thank you for your help.

[Paul Clapham]

If there's a possibility that a String might be empty, and therefore you would have a problem trying to find the first character of the String, then before you try to find the first character you should check to see if the String is empty. If it is, then do something else.