code: public static double[] multinomialGaussianSample(double[] mean, double[][] covariance) {
          MultivariateNormalDistribution gaussian = new 
              MultivariateNormalDistribution(mean, covariance);
          gaussian.reseedRandomGenerator(RandomGenerator.getThreadLocalRandom().nextLong());
          return gaussian.sample();
      }
docs: Samples from Multinomial Normal Distribution.
  
  @param mean
  @param covariance
  @return              A multinomialGaussianSample from the Multinomial Normal Distribution