Syntax error How to generate random values that won’t repeat in Java

How to generate random values that won’t repeat in Java

To generate random values that won’t repeat, use HashSet collection. Firstly, create a random object and HashSet −

Random randNum = new Random();
Set<Integer>s = new HashSet<Integer>();

Now, add random integers −

while (s.size() < 10) {
   s.add(randNum.nextInt());
}

Now, display the random numbers that are unique −

List<Integer>list = new ArrayList<Integer>(s);
System.out.println(list);

Example

 Live Demo

import java.util.ArrayList;
import java.util.HashSet;
import java.util.Set;
import java.util.Random;
import java.util.List;
public class Demo {
   public static void main(String[] args) {
      Random randNum = new Random();
      Set<Integer>s = new HashSet<Integer>();
      while (s.size() < 10) {
         s.add(randNum.nextInt());
      }
      System.out.println("Random numbers that aren't repeating...");
      List<Integer>list = new ArrayList<Integer>(s);
      System.out.println(list);
   }
}

Output

Random numbers that aren't repeating...
[-951684393, -2119833673, 1804429247, -1389537752, -1314261216, 575783898, 326063891, -1241554605, -613888875, -1698001241]

Let us see another example to get distinct random numbers that won’t repeat −

Random numbers that aren't repeating...
[1173054490, -613376175, -1947139369, -840397233, 931136232, 135129829, 1634496580, 13228721, 1929509800, 1205305181]
Updated on: 2019-07-30T22:30:25+05:30

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