How to generate a random number that do not repeat

Hello friends,

Random number generate without duplicate.

In Android

MainActvity.java

package com.samset.user.sample;


public class MainActivity extends AppCompatActivity {
   
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
     
        findViewById(R.id.btn).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                generateRandom();
            }
        });
    }


    public static void generateRandom() {
        Random rand = new Random();
        Set<Integer> set = new HashSet<Integer>();

        while(set.size() < 5) {
            set.add(rand.nextInt(9)+2);
        }

        String numStr = "";
        for(Integer n : set) {
            numStr += n;
        }
        int num = Integer.parseInt(numStr);
        System.out.print(" Random Number is  "+num);
        Log.e("TAG"," Random Number is  "+num);

    }  

}

In Java

public class Test {

    public static void main(String[] args) {

        for(int i = 0; i < 8; i++) {
            generateRandom();
        }
     
    }


Output:

1: Random Number is  87953
2: Random Number is  810953
3: Random Number is  810932
4: Random Number is  107953
5: Random Number is  410523


Thank you