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Thread: What is wrong with the call?

  1. #1
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    Default What is wrong with the call?

    This compiles and runs well:
    public class IntegerTest implements Comparator<Integer>{
    @Override
    public int compare(Integer o1, Integer o2){
    return (o1<o2 ? -1 : (o1==o2 ? 0 : 1));
    }
     
     
    /**
    * @param args the command line arguments
    */
    public static void main(String[] args) {
    List<Integer> arrayList = new ArrayList<>();
    arrayList.add(12);
    arrayList.add(5);
    arrayList.add(7);
    arrayList.add(4);
    arrayList.add(5);
    arrayList.add(16);
    arrayList.add(13);
    arrayList.add(2);
    System.out.println(arrayList);
    Collections.sort (arrayList, new IntegerTest());
    for (Integer integer : arrayList){
    System.out.println (integer);
     
    }
    }
    }
    This code creates and prints the array but gives me an error at Collections.sort.
    What is wrong with the call?
    public class ListSorter implements Comparator<Integer>{
     
    @Override
    public int compare(Integer o1, Integer o2){
    return (o1>o2 ? -1 : (o1==o2 ? 0 : 1));
    }
     
    }
    public static void main(String[] args)throws IOException {
    java.io.File intDat = new java.io.File("intDat");
    try (java.io.PrintWriter create = new java.io.PrintWriter (intDat)) {
    create.print("23 45 67 12 9 44 14 21 78 95 6 89 7 42 28 34");
    }
    Collection<Integer> intList;
    try (Scanner read = new Scanner (intDat)) {
    intList = new ArrayList<>();
    //List<Integer> arrayList = new ArrayList<>();
    while (read.hasNext()){
    intList.add(read .nextInt());
     
     
    System.out.println(intList);
    }
    }
    //System.out.println(arrayList);
     
    Collections.sort (intList, new ListSorter());
    for (Integer integer : intList){
    System.out.println (integer);
    }
     
    }
    }


  2. #2
    Super Moderator curmudgeon's Avatar
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    Default Re: What is wrong with the call?

    When you are asking about an error or exception, it makes sense to always post the error or exception message here for our review.

    --- Update ---

    Why are you asking this question twice? Please go back to your original post. Please show the error message as has been asked there.

    Locking this as an unnecessary duplicate

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