It's not good enough to simply use inheritance and apply the rules of polymorphism to your code. To write SOLID code, and properly implement the Liskov substitution principle in Java, your code must ...

Compare inheritance and composition, the two fundamental ways to relate Java classes, then practice debugging ClassCastExceptions in Java inheritance.

Learn the four types of polymorphism in Java, then start using subtype polymorphism to execute different forms of the same Java method.