What are the advantages and disadvantages of using the 'final' keyword in Java?

In Java, the keyword final is used to restrict modifications and inheritance.

Advantages:

• For variables: the value cannot be changed after initialization, which increases safety and predictability of the code.
• For methods: the method cannot be overridden in subclasses, helping to preserve logic and prevent errors during inheritance.
• For classes: the class cannot be inherited, which is useful for creating immutable or extension-protected components.

Disadvantages:

• It limits the flexibility of the code, as behavior or state cannot be changed after declaration.
• It may complicate testing and extending functionality.
• Excessive use of final can lead to overly rigid architecture.

Example:

final class Constants {
    public static final double PI = 3.14159;
}

final int maxCount = 10;

final void doSomething() {
    // cannot be overridden
}