Java provides three ways to generate random numbers using some built-in methods and classes as listed below:
- java.util.Random class
- Math.random method : Can Generate Random Numbers of double type.
- ThreadLocalRandom class
- For using this class to generate random numbers, we have to first create an instance of this class and then invoke methods such as nextInt(), nextDouble(), nextLong() etc using that instance.
- We can generate random numbers of types integers, float, double, long, booleans using this class.
- We can pass arguments to the methods for placing an upper bound on the range of the numbers to be generated. For example, nextInt(6) will generate numbers in the range 0 to 5 both inclusive.
Random Integers: 547 Random Integers: 126 Random Doubles: 0.8369779739988428 Random Doubles: 0.5497554388209912
The class Math contains various methods for performing various numeric operations such as, calculating exponentiation, logarithms etc. One of these methods is random(), this method returns a double value with a positive sign, greater than or equal to 0.0 and less than 1.0. The returned values are chosen pseudorandomly. This method can only generate random numbers of type Doubles. Below program explains how to use this method:
Random doubles: 0.13077348615666562 Random doubles: 0.09247016928442775
This class is introduced in java 1.7 to generate random numbers of type integers, doubles, booleans etc. Below program explains how to use this class to generate random numbers:
Random Integers: 536953314 Random Integers: 25905330 Random Doubles: 0.7504989954390163 Random Doubles: 0.7658597196204409 Random Booleans: false Random Booleans: true
This article is contributed by Harsh Agarwal. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to firstname.lastname@example.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.
Attention reader! Don’t stop learning now. Get hold of all the important Java and Collections concepts with the Fundamentals of Java and Java Collections Course at a student-friendly price and become industry ready.