class Result {

/*
 * Complete the 'closestNumbers' function below.
 *
 * The function is expected to return an INTEGER_ARRAY.
 * The function accepts INTEGER_ARRAY arr as parameter.
 */
public static List<Integer> closestNumbers(List<Integer> arr) {
    Collections.sort(arr);
    int mini = Integer.MAX_VALUE;
    for(int i=1;i<arr.size();i++){
        if(Math.abs(arr.get(i)-arr.get(i-1))<mini){
            mini = Math.abs(arr.get(i)-arr.get(i-1));
        }
    }
    List<Integer> result = new LinkedList<>();
    for(int i=1; i<arr.size(); i++){
        if(Math.abs(arr.get(i)-arr.get(i-1))==mini){
            result.add(arr.get(i-1));
            result.add(arr.get(i));
        }
    }

return result;
}

}