No Such Element Exception

Question

So here is my code   public static void getArmor String treasure      throws FileNotFoundException      Random rand new Random        Scanner file new Scanner new File   armor txt         while  file next   equals treasure            file next      stack trace error here               int min file nextInt        int max file nextInt        int defense min    int  Math random       max - min    1        treasure treasure replace                System out println treasure       System out println  Defense    defense       System out println               System out println           public static void getTreasureClass Monster monGet  throws FileNotFoundException      Random rand   new Random        String tc monGet getTreasureClass        while  tc startsWith  tc              Scanner scan new Scanner new File   TreasureClassEx txt             String eachLine scan nextLine            while  tc equals scan next              eachLine scan nextLine                      for  int i 0 i lt  rand nextInt 3  i                 tc scan next                  getArmor tc     stack trace error here            For some reason I get a No Such Element Exception      at java util Scanner throwFor Scanner java 907  at java util Scanner next Scanner java 1416  at LootGenerator getArmor LootGenerator java 43  at LootGenerator getTreasureClass LootGenerator java 68  at LootGenerator getMonster LootGenerator java 127  at LootGenerator theGame LootGenerator java 19  at LootGenerator main LootGenerator java 11    I m not sure why though  Basically my program is searching through two text files - armor txt and TreasureClassEx txt  getTreasureClass receives a treasure class from a monster and searches through the txt until it reaches a base armor item  a string that does not start with tc    It then searches getArmor for an armor that matches the name of the base armor it got in treasure class  Any advice would be appreciated  Thanks   The link to the txt files is here  http   www cis upenn edu  cis110 hw hw06 large data zip

User · Answer

I had run into the same issue while I was dealing with large dataset. One thing I've noticed was the NoSuchElementException is thrown when the Scanner reaches the endOfFile, where it is not going to affect our data.

Here, I've placed my code in try block and catch block handles the exception. You can also leave it empty, if you don't want to perform any task.

For the above question, because you are using file.next() both in the condition and in the while loop you can handle the exception as

while(!file.next().equals(treasure)){
    try{
        file.next(); //stack trace error here
       }catch(NoSuchElementException e) {  }
}

This worked perfectly for me, if there are any corner cases for my approach, do let me know through comments.

User · Answer

I Know this question was aked 3 years ago  but I just had the same problem  and what solved it was instead of putting    while  i hasNext             code goes here      I did one iteration at the start  and then checked for condition using    do         code goes here   while  i hasNext       I hope this will help some people at some stage

User · Answer

Looks like your file next   line in the while loop is throwing the NoSuchElementException since the scanner reached the end of file  Read the next   java API here  Also you should not call next   in the loop and also in the while condition  In the while condition you should check if next token is available and inside the while loop check if its equal to treasure

User · Answer

Another situation which issues the same problem  map entrySet   iterator   next   If there is no element in the Map object  then the above code will return NoSuchElementException  Make sure to call hasNext   first

User · Answer

It looks like you are calling next even if the scanner no longer has a next element to provide    throwing the exception   while  file next   equals treasure            file next                Should be something like  boolean foundTreasure   false   while file hasNext          if file next   equals treasure              foundTreasure   true            break     found treasure  if you need to use it  assign to variable beforehand                 out here  either we never found treasure at all  or the last element we looked as was treasure    act accordingly

[java] No Such Element Exception?

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