### Question:
PoissonDistribution extends AbstractDiscreteDistribution { @Override public double getMean() { return mean; } PoissonDistribution(double p); private  PoissonDistribution(double p,
                                double epsilon,
                                int maxIterations); @Override double probability(int x); @Override double logProbability(int x); @Override double cumulativeProbability(int x); double normalApproximateProbability(int x); @Override double getMean(); @Override double getVariance(); @Override int getSupportLowerBound(); @Override int getSupportUpperBound(); @Override boolean isSupportConnected(); @Override DiscreteDistribution.Sampler createSampler(final UniformRandomProvider rng);  }### Answer:
@Test void testParameterAccessors() { final PoissonDistribution dist = new PoissonDistribution(10.0); Assertions.assertEquals(10.0, dist.getMean()); }