Generate 10 non-duplicate random integers from 0 to 20 [duplicate]

I have a problem in generating the non-duplicate numbers. I tried to do the do-while loop but it seems not working. How do I fix it?

import java.util.Arrays;

public class Assignment2_Q2 {
    
    public static void main (String[] args){
        
        int[] myList = new int[10];
        
        number(myList);
        sortedOrder(myList);
        display (myList);
    }
        
    public static void number(int[] list){
            
        int random;
        
        random = (int)(Math.random() * 21);
        list[0] = random;
            
        for (int i = 1; i < list.length; i++){
            do{
                random = (int)(Math.random() * 21);
                list[i] = random;        
            }while(list[i] == list[i-1]);
        }
    }
    
    public static void sortedOrder(int[] list){
        
        java.util.Arrays.sort(list);    
    }
    
    public static void display(int[] list){
        
        System.out.println("The array in the sorted order:\n" + Arrays.toString(list) + "\n");  
    }             
}