Question

The following code doesn’t work though it seems quite correct:

import java.util.*;

public class Jaba {

    public static void main(String args[]) {
        Random rand = new Random();
        int[] array = new int[10];
        for (int i = 0; i < array.length; ++i) {
            array[i] = rand.nextInt(30);
        }
        Queue<Integer> que = new PriorityQueue<Integer>();
        Collections.addAll(que, Arrays.asList(array));
    }

}

What should be fixed?

Answer 1

Arrays.asList takes an array of objects. (It’s the only option, as it can’t return a List<int>.)

When you pass an int[] to Arrays.asList, it will be interpreted as a singleton array containing one int[].

You’ll have to

• Change to a for-loop:

  for (int i : array)
      que.add(i);
  

  or

• change the type of array from int[] to Integer[].

  This would allow you to do

  que.addAll(Arrays.asList(array))
  

  or,

  Collections.addAll(que, array);
  

The reason that Collections.addAll(que, Arrays.asList(array)) fails is that it takes a T... as second argument, which is really an array and not a List.