9.2 EXTRA: Writing Constructors for Subclasses

In Java, constructors are not inherited. This means that if you create a subclass, it does not automatically have the constructors of its superclass. Instead, each class must define its own constructor. If you do not explicitly create a constructor for your subclass, Java creates a default no-argument constructor that calls the superclass’s no-argument constructor for you.

You can use the super keyword to invoke the superclass's constructor. When you use super() without any parameters, it calls the no-argument constructor of the superclass. This allows programmers to simplify unnecessary, excessive code. Super() can only be invoked on the first line of the subclass constructor, otherwise it will cause a compilation error.