Final Keyword

The common characteristic of the final keyword is that attaching it means restricting something

Final Class

• Other classes cannot inherit from it

• The String class is also final!

  • Attempting to inherit the String class will cause an error

Final Method

• Other methods cannot override it

  • The method can no longer be modified

• It prevents the method from being modified while extending to sub-classes

  • It is a method that cannot be redefined in child classes, preventing child classes from changing the behavior of the parent class's method

  • This helps maintain program consistency and prevent bugs!

Final Variable

• It becomes a constant value that does not change and cannot be reassigned

• Since it cannot be modified, an initial value is mandatory

  • However, if it is a variable inside an object, initialization through a constructor or static block is allowed

• The scope of the unmodifiable value is limited to the value of that variable

  • That is, when referencing another object, the internal values of the referenced object can be changed

• public static final

  • It is a class constant that does not require an instance

  • It can be used once the class is loaded into memory

    • It is used in the form of class.constant

  • Likewise, it must be initialized at the time of declaration