How to Sort a Java Array in Descending Order?

Java Array Sort in Descending Order

An array sorting utility exists in the Arrays class to sort arrays in ascending order. However, there isn't a direct method to sort arrays in descending order.

Solution Using Comparator

To sort an array of objects in descending order, use the following code:

<code class="java">sort(T[] a, Comparator<? super T> c)</code>

<code class="java">Arrays.sort(a, Collections.reverseOrder());</code>

Solution for Primitive Arrays

For primitive arrays like int[], the above method won't work directly. Instead, follow these steps:

1. Sort the array in ascending order:

   <code class="java">Arrays.sort(a);</code>

2. Reverse the sorted array in place:

   <code class="java">reverseArray(a);
   
   private static void reverseArray(int[] arr) {
     for (int i = 0, j = arr.length - 1; i < j; i++, j--) {
    int temp = arr[i];
    arr[i] = arr[j];
    arr[j] = temp;
     }
   }</code>

Example

<code class="java">public static void main(String[] args) {
  int[] arr = {5, 3, 1, 2, 4};

  // Sort in descending order
  reverseArray(arr);

  // Print the sorted array
  for (int num : arr) {
    System.out.println(num); // 5, 4, 3, 2, 1
  }
}</code>

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