http://www.bouncycastle.org/java.html: The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5 to JDK 1.8.
  • The Legion of the Bouncy Castle Inc. 
package org.bouncycastle.crypto.test;

import java.util.Random;

class RNGUtils
{
    public static int nextInt(Random rng, int n)
    {
        return rng.nextInt(n);
    }
}