Java Basics

Syntax

"final" Keyword

• The final keyword's functionality changes based on its usage.

Variable

final int varName = 5;
varName = 6; // INVALID

• Variables with the final keyword cannot be changed. They are similar to const in C++.
• They can only be declared once. Unlike C++, they can remain undeclared until otherwise.

final int varName;
varName = 6; // VALID BECAUSE NOT PREVIOUSLY DECLARED

Within a Class

class Animal {
    final void create() {
        // do something
    }
}

class Dog extends Animal {
    void create() {} // NOT ALLOWED
}

• When used within a class, functions or variables with using final cannot be overrode. "create" being declared within Animal means that a class that extends Animal cannot implement their own create function and must use its superclass function.