May 5, 2011 · The first solution is to use the java.util.Random class: import java.util.Random; Random rand = new Random(); // Obtain a number between [0 - 49]. int n = rand.nextInt(50); // Add 1 to the result to get a number from the required range // (i.e., [1 - 50]). n += 1; Another solution is using Math.random(): double random = Math.random() * 49 + 1 ...

Min + (int)(Math.random() * ((Max - Min) + 1)) The Java Math library function Math.random() generates a double value in the range [0,1). Notice this range does not include the 1. In order to get a specific range of values first, you need to multiply by the magnitude of the range of values you want covered. Math.random() * ( Max - Min )

Random rand = new Random(); // nextInt as provided by Random is exclusive of the top value so you need to add 1 int randomNum = rand.nextInt((max - min) + 1) + min; See the relevant JavaDoc . As explained by Aurund, Random objects created within a short time of each other will tend to produce similar output, so it would be a good idea to keep ...

Feb 17, 2016 · Check How does java.util.Random work and how good is it?: In other words, we begin with some start or "seed" number which ideally is "genuinely unpredictable", and which in practice is "unpredictable enough". For example, the number of milliseconds— or even nanoseconds— since the computer was switched on is available on most systems.

Jun 18, 2016 · With Java 8+ you can use the ints method of Random to get an IntStream of random values then distinct and limit to reduce the stream to a number of unique random values. ThreadLocalRandom.current().ints(0, 100).distinct().limit(5).forEach(System.out::println);

Get Random number Returns a random integer x satisfying lower <= x <= upper. If lower > upper, returns 0. @param lower @param upper @return. In the main method I created list then i check if the random number exist on the list if it doesn't exist i will add the random number to the list. It is very slow but straight forward.

Apr 28, 2018 · This is my code to generate random numbers using a seed as an argument: double randomGenerator(long seed) { Random generator = new Random(seed); double num = generator.nextDouble() * (0.5)...

Apr 13, 2010 · java.util.Random is the more effective one I have tried out so far, having a precision of 98.65% uniqueness. I have provided bellow some tests which generate 10000 batches of a hundred 2 alphanumeric chars strings and calculates the average. Other random tools were RandomStringUtils from commons.lang3 and java.util.Math.

Apr 23, 2015 · With Java 7, one can use ThreadLocalRandom.. A random number generator isolated to the current thread. Like the global Random generator used by the Math class, a ThreadLocalRandom is initialized with an internally generated seed …

This question was asked before Java 7 release but now, there is another possible way using Java 7 (and above) API: double random = ThreadLocalRandom.current().nextDouble(min, max); nextDouble will return a pseudorandom double value between the minimum (inclusive) and the maximum (exclusive). The bounds are not necessarily int, and can be double.