What is the Final Keyword in Java?

Variables: If a variable is declared as final, its value cannot be changed after initialization. This applies to instance variables and local variables. If a reference-type variable is declared as final, the reference cannot be reassigned to another object, but the state of the object it refers to can be modified.

Methods: When a method is declared as final, it cannot be overridden by subclasses. This is primarily used to prevent overriding and ensure the behavior remains unchanged.

Classes: A class declared as final cannot be subclassed. This is typically used for designing features with high security and stability requirements, ensuring the class behavior is not modified, such as many standard library classes like String and Integer.