Thread: Collections.sort

I will try again.

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);
}
 
}
}