How to generate random numbers in Java

import java.util.Random;
class GenerateRandom {
    public static void main( String args[] ) {
      // Instance of the random class
      Random rand = new Random(); 
      // Setting the upper bound to generate the
      // random numbers in specific range
      int upperbound = 25;
      // Generating random numbers from 0 - 24 
      // using nextInt()
      int int_random = rand.nextInt(upperbound); 
      // Generating random numbers using nextDouble 
      // in 0.0 and 1.0 range
      double double_random = rand.nextDouble();
      // Generating random numbers using nextFloat
      // in 0.0 and 1.0 range
      float float_random = rand.nextFloat();
      
      // Printing the generated random numbers
      System.out.println("Random integer value from 0 to " + (upperbound-1) + " : " + int_random);
      System.out.println("Random float value between 0.0 and 1.0 : " + float_random);
      System.out.println("Random double value between 0.0 and 1.0 : " + double_random);
    }
}

class GenerateRandom {
    public static void main( String args[] ) {
       // Generate random number
        System.out.println("Random number: " + Math.random());
    }
}

class GenerateRandom {
    public static void main( String args[] ) {
      int min = 50; // Minimum value of range
      int max = 100; // Maximum value of range
      // Print the min and max  
      System.out.println("Random value in int from "+ min + " to " + max + ":");
      // Generate random int value from min to max
      int random_int = (int)Math.floor(Math.random() * (max - min + 1) + min);
      // Printing the generated random numbers
      System.out.println(random_int);
    }
}

import java.util.concurrent.ThreadLocalRandom;
class GenerateRandom {
    public static void main( String args[] ) {
      // Generate Java random integers  
      int int_random = ThreadLocalRandom.current().nextInt();  
  
      // Print Java random integers 
      System.out.println("Random Integers: " + int_random); 
      // Generate Java random doubles 
      double double_rand = ThreadLocalRandom.current().nextDouble(); 
  
      // Print random doubles 
      System.out.println("Random Doubles: " + double_rand); 
       
      // Generate Java random boolean
      boolean boolean_rand = ThreadLocalRandom.current().nextBoolean(); 
       
      // Print Java random boolean 
      System.out.println("Random Booleans: " + boolean_rand); 
    }
}

import java.util.Random;
public class Main{
    public static void main(String[] args) {
        //create an object of the Random class
        Random random=new Random();
        // stream size
        long streamSize = 10;
        // using ints generate stream of random ints
        System.out.println("Random stream:");
        random.ints(streamSize).forEach(System.out::println);
        System.out.println("Range bound random stream:");
        random.ints(streamSize, 5, 11).forEach(System.out::println);
    }
}

import java.security.SecureRandom;
class GenerateRandom {
    public static void main( String args[] ) {
        // Instance of the SecureRandom class
        SecureRandom rand = new SecureRandom();
        // Setting the upper bound to generate 
        // the random numbers between the specific range
        int upperbound = 1000;
        // Generating Java random numbers from 0 - 999
        // using nextInt()
        int int_random1 = rand.nextInt(upperbound);
        int int_random2 = rand.nextInt(upperbound); 
        // Generating Java random numbers using nextDouble 
        // in 0.0 and 1.0 range
        double double_random = rand.nextDouble();
        // Generating Java random numbers using nextFloat 
        // in 0.0 and 1.0 range
        float float_random = rand.nextFloat();
        // Printing the generated Java random numbers
        System.out.println("Random integer value from 0 to " + (upperbound - 1) + " : " + int_random1);
        System.out.println("Random integer value from 0 to " + (upperbound - 1) + " : " + int_random2);
        System.out.println("Random float value between 0.0 and 1.0 : " + float_random);
        System.out.println("Random double value between 0.0 and 1.0 : " + double_random);
    }
}