In this post we will go through the basics of generating random numbers and also see how they can be generated within a range along with best practices. Java provides support to either generate random numbers through java.lang.Math package or java.util.Random . Using java.lang.Math There exists a static method inside this class, Math.random . It is very convenient to use and returns a double between the range 0.0 and 1.0 i.e. it returns a floating point number between 0 and 1. public static void main(String[] args){ double randNum = Math.random(); System.out.println(randNum); } Random number within a range - To generate a random number within a range we need to further process the number returned by Math.random() public static void main (String[] args){ double min = 10.0; double max = 100.0; double randNum = randRange(min, max); System.out.println(randNum); } public static double randRange(double min, double max){ double x = (Math.rando