Java implementation probability calculation

Programs often encounter random send red envelopes and other scenarios, this random also have to specify the probability, such as 10% of the chance to get red envelopes. So how does Java implement a simple probability calculation, see the following example:

int randomint =  randomutils.nextint (1,101); if // 100 inside 1 numbers, the probability of being less than or equal       to 10 is 10% // Do Something}

The Randomutils tool class is inside the Commons-lang3 bag.

<Dependency>    <groupId>Org.apache.commons</groupId>    <Artifactid>Commons-lang3</Artifactid>    <version>3.7</version></Dependency>

Java implementation probability calculation