How to do the sorting for duplicate numbers in Java?

Question

Now I want to do the sorting part... What is sort? And I so confused about sorting and I need to remove the duplicate numbers... And how to do remove numbers and sort for this coding? p/s:The duplicate numbers I only got a few...

import java.lang.*; 
// import java.util.Random;

class UniqueRandomIntArray {

//   static Random rnGen = new Random();

   private static void uriArray(int[] rray) {
      int low = 0;
      int high = 100;

      int rn;
      int haveit = -1;
      int i = 0; 
      int j;

      while((haveit == -1) && i < rray.length) {  
         rn = randNum(low, high);

         for(j = 0; j <= i; j++) {
            if(rn == rray[j]) {
               haveit = j;
               j = i;
               }
            }

         if(haveit != -1) {
            System.out.println("a[" + haveit + "] is " + rn + " already");
            haveit = -1;
            }
         else {
            System.out.println("a[" + i + "] is " + rn);
            rray[i] = rn;
            i++;
            }

         }   // end while
      }      // end uriArray


   private static int randNum(int min, int max) {
      int range = (max - min) + 1;
//      int randnum = rnGen.nextInt(range) + min;
      int randnum = (int) (Math.random() * range) + min;
      return randnum;
      }


   public static void main(String[] args) {
      int[] arra = new int[20];
      uriArray(arra);
      for(int i=0; i<arra.length; i++)  {
         System.out.print(" | " + arra[i]);
         }
      System.out.println(" | ");
      }

   } //class ends

Answer 1

Here is an easy way to generate a unique, random list of ints:

    new Random().ints(0, 101)// generate a stream of random integers from 0 (incl.) to 100
            .distinct() // unique                                   
            .limit(20) // we only need 20 random numbers
            .sorted() // sort
            .forEach(System.out::println);

So if you want the same result as in your old code, this is your complete new code:

class UniqueRandomIntArray {
public static void main(String[] args) {
    new Random().ints(0, 101).distinct() // generate a stream of random
            // integers
            .limit(20) // we only need 20 random numbers
            .sorted().forEach((int i) -> System.out.print(" | " + i));
    System.out.println(" | ");
}
} // class ends

Answer 2

Replace below code with your current main method and run the program.
for ascending order result use this
Arrays.sort(result);

for descending order result use both
Arrays.sort(result);
Arrays.sort(result, Collections.reverseOrder());

 public static void main(String[] args) {
      int[] arra = new int[20];
      uriArray(arra);

      Integer[] result = new Integer[arra.length];
        for (int i = 0; i < arra.length; i++) {
            result[i] = Integer.valueOf(arra[i]);
        }       
      Arrays.sort(result);          
      Arrays.sort(result, Collections.reverseOrder());  //comment this line if you want only ascending order results. if you want descending order result keep this line alive

      for(int i=0; i<result.length; i++)  {
         System.out.print(" | " + result[i]);
         }
      System.out.println(" | ");
      }

Let me know if this works for you

Include these packages

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;