Exception in ArrayList in java

Question

public static int getMin(int[] arr, int min,int max,int a){
    Integer[] test = Arrays.stream(arr).boxed().toArray(Integer[]::new);
    List<Integer> list =null;
    list = new ArrayList(Arrays.asList(test));
    list.removeAll(Collections.singleton(0));
    min = Collections.min(list);
    max = Collections.max(list);

    if(a == 0) {
        return min;
    } else {
        return max;
    }
}

List item

Exception in thread "main" java.util.NoSuchElementException
    at java.util.ArrayList$Itr.next(ArrayList.java:862)
    at java.util.Collections.min(Collections.java:596)
    at Solution.getMin(Solution.java:47)

What is the reason for this exception?

it depends on input, and for that question inputs are given on runtime — Shubham Sharma
– Shubham Sharma, Commented May 23, 2020 at 5:21
As a side note, this is a horribly inefficient way to get the minimum or maximum from an array. Your very first line does already contain a Stream operation, so why not let the Stream return the intended result in the first place: IntStream is = Arrays.stream(arr).filter(i -> i != 0); OptionalInt result = a == 0? is.min(): is.max(); Then, you have to decide what to do if the result is empty, e.g. return result.orElse(0); — Holger
– Holger, Commented May 24, 2020 at 10:37

Basil Bourque · Accepted Answer · 2020-05-23 06:07:41Z

1

Empty collection

The Javadoc for Collections.min states that passing an empty collection will throw a NoSuchElementException.

Add a test for List::isEmpty before checking the minimum and maximum.

answered May 23, 2020 at 6:07

Basil Bourque

347k130 gold badges950 silver badges1.3k bronze badges

Sign up to request clarification or add additional context in comments.

Comments

djm.im · Accepted Answer · 2020-05-23 06:10:12Z

1

You passed an array that contains only zeros. And this line of code removes all zero elements list.removeAll(Collections.singleton(0));. After this, the list has size zero - no any elements in it.

Here is an example to reproduce the exception

private static void getMin() {
    List<Integer> list = new ArrayList<>();

    Collections.min(list);
}

answered May 23, 2020 at 6:10

djm.im

3,3334 gold badges32 silver badges47 bronze badges

Collectives™ on Stack Overflow

Exception in ArrayList in java

2 Answers 2

Empty collection

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Empty collection

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related