In this post, we will see about Java math random example.

Math’s random method provides you positive signed double value from 0.0 to 1.0.

## Syntax

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public static double random() |

If you see the source code for random math, you will see that it uses

**java.util.Random**class’s nextDouble() method to generate random number between 0.0 to 1.0.

**Source code of Math’s random() method**

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private static Random randomNumberGenerator; private static synchronized void initRNG() { if (randomNumberGenerator == null) randomNumberGenerator = new Random(); } public static double random() { if (randomNumberGenerator == null) initRNG(); return randomNumberGenerator.nextDouble(); } |

## Example

Let’s say you want to generate random integer from 1 to 10. You can use Math’s random method as below:

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/* * returns random integer between minimum and maximum range */ public static int getRandomInteger(int minimum, int maximum){ return ((int) (Math.random()*(maximum - minimum))) + minimum; } |

Pass maximum as 10 and minimum as 1.You will get random integer between 1 to 10.

Here is the complete example:

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package org.arpit.java2blog; public class MathRandomMain { public static void main(String[] args) { System.out.println("Math's random method output"); for (int i = 1; i < 10; i++) { System.out.print(" "+Math.random()); } System.out.println(); System.out.println("Generating random number from 1 to 10"); for (int i = 1; i < 10; i++) { System.out.print(" "+getRandomInteger(1,10)); } } /* * returns random integer between minimum and maximum range */ public static int getRandomInteger(int minimum, int maximum){ return ((int) (Math.random()*(maximum - minimum))) + minimum; } } |

When you run above program, you will get below output:

0.6094762145403727 0.984629643759588 0.1391747855327513 0.03367790074630195 0.7327997405792047 0.29391413463517546 0.2757890922600933 0.19606812863092626 0.8941801486372356

Generating random number from 1 to 10

6 8 0 5 8 5 5 0 3

You can use java.util.Random class’s nextInt method also to get random integer values from 0 to 10.

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package org.arpit.java2blog; import java.util.Random; public class MathRandomMain { public static void main(String[] args) { System.out.println("Generating random number using Random's nextInt"); Random random=new Random(); for (int i = 1; i < 10; i++) { System.out.print(" "+random.nextInt(10)); } } } |

When you run above program, you will get below output:

9 7 4 3 7 1 7 2 5

random.nextInt(10) method will generate random integer between 0 to 10.

that’s all above Math’s Random method.