Use Java's extends keyword to derive a child class from a parent class, invoke parent class constructors and methods, override methods, and more.

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.

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.