How Java array covariance is bad

ArrayCovarianceTest.java

import org.junit.Test;

public class ArrayCovarianceTest {

	@Test(expected = ArrayStoreException.class)
	public void cat_should_not_be_set_in_dog_list() {
		Animal[] animals = new Dog[1]; // array covariance

		// Java compiler allows the assignment because Dog extends Animal 
		// But the Java runtime throws a "java.lang.ArrayStoreException: Cat"
		animals[0] = new Cat();
	}

	class Animal {

	}

	class Dog extends Animal {

	}

	class Cat extends Animal {

	}
}