Sealed classes in Java let developers limit the creation and use of subclasses and preserve the class hierarchy. Here is how sealed classes in Java work.

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

A Java class inherits these methods and can override any method that’s not declared final. For example, the non- final toString() method can be overridden, whereas the final wait() methods cannot.