1、产生随机数

import java.util.Random;

public class RandomTest
{
    public static void main(String[] args)
    {
        Random random = new Random();

        for(int i = 0; i < 50; i++)
        {
            System.out.println(random.nextInt(41) + 10);
        }
                
    }
}

方法2：

import java.util.Random;

public class RandomTest
{
    public static void main(String[] args)
    {
        Random random = new Random();

        for(int i = 0; i < 50; i++)
        {
            double result = Math.random();
            result *= 41;
            int result2 = (int)result;
            result2 += 10;
            System.out.println(result2);
        }           
    }
}

2、随机生成50个数字（整数），每个数字的范围是[10, 50]。统计每个数字出现的次数及出现次数最多的数字与它的个数，最后将每个数字及其出现次数打印出来。如果某个数字出现次数为0，不打印。打印时，按照数字升序排序。

import java.util.Random;

public class RandomTest2
{
    public static void main(String[] args)
    {
        int[] count = new int[41];

        Random random = new Random();

        for(int i = 0; i < 50; i++)
        {
            int number = random.nextInt(41) + 10;

            count[number - 10]++;
        }

        for(int i = 0; i < count.length; i++)
        {
            if(0 == count[i])
            {
                continue;
            }

            System.out.println((10 + i) + "出现次数：" + count[i]);
        }

        int max = count[0];

        for(int i = 0; i < count.length; i++)
        {
            if(max < count[i])
            {
                max = count[i];
            }
        }

        System.out.println("出现的最大次数为：" + max + "次");

        for(int i = 0; i < count.length; i++)
        {
            if(max == count[i])
            {
                System.out.println(i + 10);
            }
        }
    }
}