Interesting usage of random numbers in java

It is easier to understand 

package com.wz.other; 

import java.util.Random; 
import java.util.concurrent.ThreadLocalRandom; 

/** 
* Interesting features of random 
* 
* @author Administrator 
* @create 2018-04 -23 8:42 
*/ 
public class UseRandom { 

    public static void main(String[] args) { 
        // simple usage 
        // yields double precision floating point numbers between 0.0 and 10.0 
        double num = Math.random() * 10; 
        // Generate integers between 0 and 10 
        long num1 = Math.round(Math.random()*10); 

        // Advanced usage (create Random object every time) 
        Random random = new Random(); 
        int num2 = random.nextInt(10); 

        // Concurrency scenario (jdk1.7), two advantages, single instance static access, as flexible as Math.random()
        int num3 = ThreadLocalRandom.current().nextInt(10); 

        // Experience sharing 
        Math.round(Math.random() * 10); // Unbalanced distribution and rounding effect 
        Math.floor(Math.random( ) * 11); // The problem above can be solved 

        // In actual combat projects, do not use the first method below to get integers, but use the second method 
        Random rnd = new Random(); 
        // The first method One method 
        System.out.println(Math.abs(rnd.nextInt()) % 10); 
        // The second method 
        System.out.println(rnd.nextInt(10)); 

    } 
}